Feel so left out but it's my own fault

Well I was actually able to bring my self to go to a New Year's day open house at a childhood friend's home. Up until we actually left the house I wasn't sure if I was going to go and my husband had already mentioned that he would go with the kids if I wasn't feeling up to it. As soon as we got there I regretted the decision to go. There were sooooo many people there. I started to feel the temperature rise and the sweat beads start to form. I was trying to make my way to my mom but it was difficult to get through all the people. I almost passed out from the lack of air. Then the kitchen cleared out and there was only 2 or 3 people in the kitchen that I didn't know or feel comfortable with. Then again the next wave of visitors came and again the anxiety kicked in. It was really intense. I almost passed out again. My children had bolted to the basement where the other kids were, so I slowly made my way down there. Once I was down there I felt so much better. It was cooler and there were only 2 other adults down there. One of which was my husband. I spent the remainder of our 1 1/2 hr visit down there. Then upon leaving you couldn't get me out of there faster. I bolted for the door. I think my friend may have been insulted but not sure as she is one of the few people that know about what I'm going through. I can't help but feel so left out of everything. All my other childhood friends still get together and do dinners at each others houses. I never get an invite. At the parties that I do finally get my self to I feel so secluded. I know I do it myself. I sit in a corner or away from everyone and don't talk to anyone unless they start the conversation first. I know that this is all my own fault and that no one is purposely leaving me out. But then I feel like I'm being left out because I'm being judged or they don't like me. Even when I try to reconnect with old friends it seems like no one is responsive.

I know that I have done this to myself by being weak and letting this agoraphobia and depression win over me. I just don't know what I can do get back that strong, friendly, social girl I used to be before my daughter was born. I hate not having any energy to do anything, and being too scared to do anything. How am I going to get passed this?