Can't meditate anymore

I think you are assailed with Vitakka and Vicara. This is a common activity of our mind. Be aware of these thoughts. If they are wholesome (Samma Sankhappa) then they are OK.

Don't worry. Its just a natural lack of mindfulness due to the time not engaging in (mindfulness) meditation practice.

Stay consistent with your method of practice and don't let too much time pass between formal sittings. Do short sessions of 15-30 minutes and gradually increase sitting time, as your faculties strengthen. With correct and consistent practice, mindfulness and insights will arise again.

Its just like heating water. Your pot has been standing on a cold stove for a while. Turn on the heat again and the water will eventually boil.

If you practice Vipassana meditation then you might want to limit yourself to 1 or 2 of the Four Sattipathanas and gradually increase the amount of objects.

If you do Samatha meditation then reaffirm your intentions (whether they are wholesome or not) for doing the practice, practice skillful efforts and start out with short sessions. Its even more important here to do short sessions in the beginning, due to the concentrated nature of this practice.

Lastly, investigate the five spiritual faculties and find out where they are unbalanced and then work on balancing them.

Hope this helps. Feel free to contact me if any help is needed.

Such deep lapses of the awareness happen because of tension. If you try to keep awareness moment to moment, the longer you do it and the harder you try, the more dramatic lapse will happen. I recall when I tried to keep stable tight grip of awareness, eventually I discovered myself floating among dream-like images.

Perhaps the same mechanism worked in your case: your mind eventually got tired, and its attention started to wander - that's a way to give the brain some rest.

Apart from that, I don't know, are there any pathological processes involved in your case or not.

Another point: with meditative practice people develop such strong concentration that the perception of time and place might disappear. For example, you meditate or do some other calm, meditative things, and suddenly you discover that much time has passed. I recall once when I painted my self-portrait and finally got more or less satisfied, I stretched my back, looked around and wondered, why the light was on. It was not dark yet. So why did I turn on the light? I went to the kitchen to look at the clock. It was almost half past ten. So it was late, then why it was not dark outside? I looked out of the window. Was there a nuclear war, a comet falling or something? Why the sky was bright? But people walked down the street quite calmly, as if nothing unusual was happening. So gradually I realized that it was morning already.

Such experience might be called samadhi - deep meditative absorption. A practitioner is so immersed in his activity - sitting meditation or something else - that doing it he might not notice that several days passed. There is a story of some practitioner who lived secluded in mountains. He boiled himself some porridge, but before eating he decided to meditate a bit. Soon shepherds came and asked why he didn't visit their village for some time. He didn't realize that several days had passed, but when he opened his pot of porridge, he saw there long strands of mold.

When the control over our actions is lost, it's probably not samadhi, but mental wandering. However that wandering had deep concentration, that's why the awareness was lost so completely. The moment of losing control likely happened because the brain got tired of tension.

That's a basic explanation which I can think of. Not sure, is your brain in good health or not, such tension can be not a very healthy sign, though not necessarily. In any case, take a good care. Investigate: which habits create the excessive tension in your body-and-mind? What are the causes? Change those causes in your life and abandon those unhealthy habits.

Direct your practice at developing more openness and relaxation.

Don't grasp meditation so tightly. Rather, let it be relaxed. It' like putting an object down, rather than squeezing it in your hands.

When it lies on the ground, it won't run anywhere, so relax and let it stay. Let yourself stay, relaxed and unconstrained.

Even if your mind starts to wander, it's better to follow that wandering and remain aware, rather than struggling with it and eventually losing the awareness at all.

The ultimate mastery in meditation is effortless.

Good health to you!

Distraction could be due to Restless Worry which is one of the Hindrances.

This is due to unwise attention:

There is unrest of mind; frequently giving unwise attention to it — that is the nourishment for the arising of restlessness and remorse that have not yet arisen, and for the increase and strengthening of restlessness and remorse that have already arisen.

— SN 46:51, The Five Mental Hindrances and Their Conquest Selected Texts from the Pali Canon and the Commentaries compiled and translated by Nyanaponika Thera

Also see this answer.

Wise attention can help with your wondering mind

There is quietude of mind; frequently giving wise attention to it — that is the denourishing of the arising of restlessness and remorse that have not yet arisen, and of the increase and strengthening of restlessness and remorse that have already arisen.

— SN 46:51

These things should be avoided:

When the mind is restless it is not the proper time for cultivating the following factors of enlightenment: investigation of the doctrine, energy and rapture, because an agitated mind can hardly be quietened by them.

Following should be cultivated

When the mind is restless, it is the proper time for cultivating the following factors of enlightenment: tranquillity, concentration and equanimity, because an agitated mind can easily be quietened by them.

— SN 46:53

It's not a problem. It's the human mind. Meditation is not meant to stop thought. It's meant to help you notice "what is". You have noticed how busy and restless your mind is. That is good. As you get more into your practice again you will notice more moments of stillness also. Just accept where you are at and let go of any expectations for things to be any differently or the way they used to be.