I'm sorry to read that you're going through all that. You deserve to love yourself and your body.
The first thing that comes to mind is that maybe that porn you saw at an early age set up your mental image early of what naked bodies "should" look like, which is usually highly unrealistic, and you started to compare your own body to theirs. A lot of self hatred comes from comparing yourself to others. Everyone is unique, so there's really no need to compare.

Perhaps there may be some deeper things going on as well, like parental issues, either being abused or neglected.