i can only tell you what i feel like when i think i am "breaking down" which has never really happened. i think my "break downs" are mostly fear that i am going to "break down".
to me, a "break down" feels like i am about to "lose control" which sometimes leads to the decision to act out sexually or violently, which puts me back "in control" in my confused mind. if i "choose" to "lose control" then i am still "in control".
the only alternative i have to the "break down" is the "shut down". the inner conflict between what i should do and what i want to do turns into lack of activity and emotion, which i discovered is depression, even though i do not feel sad. i call it my "spock" routine. i imagine emotions are for fools and i feel nothing. but this can manifest into the "robot" or "auto-pilot" and even "cruelty". i used to brag that i had a heart of stone. this was never true.
so, in my case, it is all based around the illusion that i control the situation, which is an outright fantasy. i control nothing but my own behaviour. this self-knowledge seems to disappear during the panic or depression.
i have since discovered that the "pain" and "anger" is nothing but fear. the fear is based on the inner truth that i have no power over other people or mother nature.