Do monks have big ups and downs in their life?

Evryperson can take things to be a part of their life or they can just ignore it. It depends how attached a person is to a certain object,person. More a person meditate,less atached they get and hence there is less waries.

Could we not just ask ourselves, "do we have ups and downs in our lives. If so, then is this not a sign that Buddhism does not strip you of humanhood, but teaches you to assume a more mindful perspective.

a more extensive study can be found here http://viewonbuddhism.org/depression.html

Assuming that monks try to progress in meditation one can assume that from that alone a lot of ups and downs will get created. Seems also to depend on the specific lineage, see e.g. Mahasi vs PaAuk-developments, and personal predispositions.

I personally met a Thai monk in a Chiang Mai meditation place who was really in a permanently dark mood with super high reactivity to the extend that it seemed a parody with a comical aspect while appearing truly desperate. He was charged with attending to the foreign meditators and being familiar with such states I liked him somehow for that ('...this is our [meditation center] dog here. Its the only friend I have. Good dog...'). It was a very interesting basic meditation instruction he delivered. Hope he is out of that now and got a different chore too.

Then also, voluntary disrobing is not uncommon, if that counts as a crisis.

You can find many more stories online.

Ajahn Brahm sometimes spoke on his YouTube talks about junior monks (including him) being mistreated by an elder monk in Thailand when it came to alms food (please see this answer for details), and he also spoke about his experience with hospitalization due to malaria where his teacher Ajahn Chah visited him and gave a teaching, and at another time, diarrhea.

He also spoke once about misplacing some object (something like a screwdriver or spanner or hammer) and forgetting about it, then reprimanding his subordinate monks as the abbot, for not returning things to their proper place. But later he discovered that it was his own fault.

He also spoke briefly about his euphoric meditation experiences although as a monk, he cannot share his spiritual achievements in detail with lay persons.

His teacher Ajahn Chah was unable to walk and talk in his old age due to chronic non-communicable diseases, if I'm not mistaken.

His predecessor in the role of the abbot of the Bodhinyana Monastery, Ajahn Jagaro, disrobed to marry a woman he fell in love with.

Of course! You don't liberate yourself from suffering just by ordaining.

Whether or not they have big ups and downs depends on conditions and what you mean by ups and downs. Some monks get really down when they aren't enlightened, and really up when they experience peace.

The only one who is free from ups and downs is one who is free from dukkha. :)

Monks are humans too. They experience the same ups and downs in terms of how meditation practice goes. Also any emotional upheavals. But conditions are more suitable for serious practice.

Since abandoned worldly affairs the chances of stress from these sources (responsibility, obligations, need to earn or work) are not there.

Since you don't own much stress from ownership of property doesn't happen.

Since your influence on the world (power, positions) has been abandoned stress from these areas don't arrise.

Since you have abandoned class, cast, clan, relatives, friends, family, etc. any distractions from these sources are eliminated.

Take a look at Ajahn Lee's autobiography, page 16 and onward.

His practice slackens, he grows disillusioned with being a monk, and he begins an obsessive debate within himself about whether to disrobe or not:

But looking at the state of my meditation, I could see that my practice had grown slack. I was becoming more and more interested in worldly matters. ...

One day I went up to a hollow space at the top of the chedi and sat in meditation. The theme of my meditation was, 'Should I stay or should I disrobe?' Something inside me said, 'I'd rather disrobe.'

... 'The people in the Great Metropolis aren't deva-sons or deva-daughters or anything. They're people and I'm a person, so why can't I make myself be like them?'

I questioned myself back and forth like this for several days running until I finally decided to call a halt. If I was going to disrobe, I'd have to make preparations. Other people, before disrobing, got prepared by having clothes made and so forth, but I was going to do it differently. I was going to leave the monkhood in my mind first to see what it would be like.

So late in the quiet of a moonlit night, I climbed up to sit inside the chedi and asked myself, 'If I disrobe, what will I do?' I came up with the following story.

If I disrobe, I'll have to apply for a job as a clerk in the Phen Phaag Snuff and Stomach Medicine Company. I had a friend who had disrobed and gotten a job there, earning 20 baht a month, so it made sense for me to apply for a job there too. I'd set my mind on being honest and hard-working so that my employer would be satisfied with my work. I was determined that wherever I lived, I'd have to act in such a way that the people I lived with would think highly of me.

As it turned out, the drug company finally hired me at 20 baht a month, the same salary as my friend. I made up my mind to budget my salary so as to have money left over at the end of each month, so I rented a room in the flats owned by Phraya Phakdi in the PratuuNam (Watergate) section of town. The rent was four baht a month. Water, electricity, clothing, and food would add up to another eleven baht, leaving me with an extra five baht at the end of each month. ...

I won't paste it all, as this goes on and on for several pages in insane detail as he imagined what might happen if he disrobed. I think the amount of detail is indicative of how much he wanted to disrobe right then and return to lay life.

But he concludes:

Finally I decided to call a halt. My wife wasn't what I had hoped for, my earnings weren't what I had hoped for, my children weren't what I had hoped for, so I left my wife, was reordained and returned to the contemplative life.