Your sister's onto something. You've resisted the same recommendation from me, my husband, and from others here.

Going to a counselor doesn't mean you have to stay in treatment forever. But a good one can make a world of difference. It's understandable with all your anxieties and social unease you'd be wary of taking that step. But if you can find one who is kind and perceptive and stick with him/her past the initial flight response when you start getting down to the brass tacks of what's up with you (you'll want to terminate treatment and run for the hills when that happens, knowing you), you will benefit immensely. So will the people who care about you.

THCBongman's right. There are a lot of folks who care about you and are your friends. Right here. Me included. I've sought treatment for anxiety, PTSD and depression myself. It takes a heck of a lot more courage to work on yourself than to keep living as an emotional invalid. You have that courage. I know you do. I've seen you display it here in numerous ways.