Hey.

I'm sorry if this may not fit so much here. I normally don't talk about my own issues on Reddit, but this is something that I've been desperate to try to figure out.
First, I would like to say that I have schizoaffective disorder (bipolar subtype), BPD, and CPTSD.

I'm sometimes running into episodic waves of extremely intense mental pain. These are much more painful than my major depressive episodes, which are more in line with very long lasting, consistently severe feelings of hopelessness and lethargy.
However, this episodic anguish is something uniquely perplexing.

To explain, the day may be going alright and not much different than it generally does, but seemingly out of nowhere, I'm hit with this feeling of overwhelming torment. Sometimes, it also happens as a response to very simple things, such as being asked if I've made sure to drink some water. 

It is so painful that I can barely explain the feeling itself, and only really what I end up doing when it happens.

I hold my breath, my whole face flinching strongly, eyes squinting shut, tears starting to stream down, accompanied by groaning noises that sound incredibly harrowing to those around me. My entire body tenses up and contorts, making writhing movements. Lastly, the distress will hit such an excruciating point during which I start punching my own legs, or repeatedly slamming my hand on whatever surface may be nearby. Usually my desk, or my pillows when I'm in bed. 

This anguish will last for about a couple minutes and will then vanish suddenly. Once I'm experiencing a wave, they never come alone. There will always be multiple ones following shortly after I'm catching my breath from the previous one. After about ~4-6 of these waves, the episode will usually fade for good, leaving me completely exhausted from it all until the cycle repeats. This may be in a few hours, or even days. Afterwards, I'm always left with drool all over myself, gasping for air, now groaning from exhaustion. The only words I'm able to utter are "Holy shit".

Is there anybody out there that may be able to shed some light on this? Perhaps somebody with a similar experience?