i have had various types of dissociative experiences including derealization and depersonalization. i also have OCD though, and years ago it got really bad. the combination together nearly drove me crazy (no pun intended). i was questioning my existence, what religious beliefs were 'right' or 'wrong,' and many other things. it caused a lot of upset and distress, anxiety and panic attacks, and other related things.

for me, it was several things that co-existed. i couldn't find a way to make it stop, but several years later a lot of the things that happened at that specific time did lessen.

it was a matter of things within myself and life changing, so more of a maybe developmental aspect to things as a lot of was during high school and early adulthood years which is often when we are still trying to figure out who we are, what we believe in, etc., so the combination, i think, can cause a type of existential crisis which if you are prone to anxiety/panic can cause those issues as well as derealization as a component as it's overwhelming, confusing, and scary to go through.

you could have a form of OCD since you mention bad thoughts in your head. that was something i also struggled with as well as urges, images, etc. a lot of them were violent and scary and terrified me. i couldn't make them stop..but again, there was the derealization aspect since anxiety can cause that to happen too in some people.

i would speak to a professional about it for sure because things like that can be more of an anxiety/panic or OCD related issue with the derealization being triggered due to the overwhelming aspect and your brain not being able to stop it.