Upvote:3
If your breathing, body & mind are currently functioning normally, I would forget about it because your question is an example of 'attachment', which Buddhism teaches to let go of.
Naturally, I can't say exactly what happened, whether the cause was purely mental (a cathartic emotion); or otherwise purely energetic due to some kind of (non-Buddhist) yogic energy manipulation? But obviously what you regarded as "deep" was merely something unnaturally forced & temporary. It sounds like you pushed to some kind of limit in your energetic-breathing-nervous-system due to non-Buddhist yogic practice.
You should ensure your breathing is currently normal because excessive yogic practises can bring harm to the body, breathing & nervous system.
Buddhist meditation has its foundation in letting-go & non-attachment rather than pushing or manipulating.
Below is an example of a yoga practice called 'pranayama', which is a deliberate controlling of breathing: