Welcome.
It's very hard going from an emotional support beam to suddenly being free of the weight because all that worry/stress has no where to go of the sudden you start thinking you should have done more (FOG: fear, obligation, guilt), especially if they start spiraling downward.
Hold on to the good moments, but do take a critical look at them. If they were honestly good moments, cherish them. I had a 'good' visit with my parents a few months ago, at least that's what I thought until I realized that the entire visit I was belittled and criticized but just because it wasn't
as bad as usual didn't mean that it was good.
I totally agree that it is hard to make friends when you have someone who has spent your life sewing seeds of distrust in your relationships. Abusive people isolate their targets and try to crumple the foundations for future healthy relationships because it means that targets won't have anyone else to fall back on. Learning to trust again is one of the hardest steps in moving forward and making friends because it means making yourself vulnerable to someone else.
Friendship is never a burden, it's a give and take relationship. It's also not being a burden to need help. Everyone needs help at one time or another. But it
is hard to reach out. It tends to be easier to reach out anonymously, simply because the vulnerability level is lower. Though, I remember when I first started posting

I was terrified of what people would say.
But, Welcome. And don't be afraid to 'talk it out' on the boards.
SC