I sabotage myself and my potential friendships/relationships but I don't really know why.

I feel this way too. I would love a romantic relationship and even friends again, but I truly feel unwhole and therefore not equal to others. I read in my book CBT For Dummies , that depression will say, Stay away from people, stay in bed, etc. but we have to do the opposite of what depression or the trauma etc says. So that means go out for a bit, or talk to someone or even just be near others to start. I liked that idea. Because it's not the true you, no.
It's still tough because I know many are energy sucking, narcissist, etc. but if we put up boundaries, it's worth the try I think. I'm so tired of feeling isolated.