Oh hun I know exactly what you're feeling. It's so much to handle even when there are people around who are willing to listen, but when you're unable to have those kinds of people around you it's even more of a struggle. But with that said, it's not a life sentence. I'm in the same boat as you. I have no friends, all of my "best" friends still keep in touch with me here and there, but not in person, and if I ever leave the house it's most likely just to go shopping with my family. No job, no money for myself, and my significant other seems to have better things to do than listen to be "bitch and moan" about how horrible I feel. It's really up us to love ourselves.
In my battered mentality I try to understand that not everyone can handle people's traumas if they themselves have never had any/a lot to haunt them. PTSD isn't all that rare, but it isn't easy to find others who know how to handle someone who has it. They get overwhelmed, and scared, and some may even use it to benefit them in some way by belittling you for it. That's horrible that there are people out there who are twisted enough to reopen our old wounds to gain some sick pleasure from it. Many people are just so superficial that to dive into the mind of someone with trauma and help them get through it is just too hassling for them. They're missing out on the most amazing people by passing them up for a cheaper artificial relationship.
You're not alone even if your situation makes you feel that you are. DID is a complicated and not very socially informed disorder, so maybe if the people around you aren't so great it's best they don't know. If someone who deserves your trust were to know you in this aspect the would not use it against you! There are plenty of ways to have an outlet for these anxieties and built-up feelings, and not in person is better than not at all

. If it wasn't for this forum, I'd be ripping hair out as I speak haha. There is nothing wrong with wanting to pay attention to yourself for once, that doesn't make you selfish by any means. We all need love, especially self love that we usually deny before denying love to others. In fact, I know you and I both would rather explicitly shower someone else with love and attention before we ever turn that affection on ourselves. The people we have given that to didn't even give it back, so why not spend some of that love on us?
One day you will be able to break free of this isolated feeling and the people around you will see how brave you are. You don't need a purple heart to be a hero for overcoming something so difficult.