Why am I struggling to maintain conversation and how can I fix this?

I have been feeling quite depressed recently but suddenly I’m more nervous around people. I don’t know what to say when people talk to me, I just say ‘yeah’ it’s like my brain freezes up. I can’t follow group conversations when I’m in a bar with friends , they all seem to be able to cope with loud noises. I feel anxious about my appearance and the way I sound and when I do talk it comes out wrong and all awkward. It never used to be this bad, but it’s scaring me a bit cause I want to enjoy conversation again. I want to make new friends but I feel so anxious around new people. It’s like I can’t have deep conversation and screw up my words. I’m scared I could have aspergers or something!! How can I stop all this!??