I have a really embarrassing story

How do I start this? This problem started from childhood and i am 23 now. I was assaulted as a child and think it’s why this thing started. I would hold my poop in a lot.. I guess I liked the feeling of the pressure. it went on to holding the poop in and pushing it out slightly and pushing it back in using my muscles. As I’ve grown it’s gotten a lot worse. To get to the point, it’s turned into fisting but not in and out kinda pulsing my hand back and fourth along my rectum. I can’t explain why I do this behaviour, it’s like I can’t help it and I need to do it, especially during stressful periods of life. I’m worried I’ve damaged myself because it’s bleed before and has been painful. It always recovers tho. I’m having a problem with going to the toilet, the slightest strain my rectum is mildly prolapsing. Starting today, am no longer doing this embarrassing thing and doing some kegals to hopefully help it? Hopefully things will get better soon. Again, there’s no pain, no bleeding. I don’t know why am telling Reddit but I’ve kept this to myself for so long, maybe there’s others who have the same problem?