I don't know if its social anxiety as such but, I'm no good in social situations...
I'm dead quiet, and it usually takes one person a fair bit of time to get me out of my shell... Say I was at a party with a few people, and I only knew one of them... I'd cling to that person or sit on my own until I had the whole situation figured, and even then I wouldn't talk to anyone before they talked to me... but maybe this is just shyness?? I don't know... I do get a bit claustraphobic in situations like that but, doesn't everyone really?? I think its more a case of me thinking that I'm not actually that interesting or funny, and when someone finds me so, I never realise it until its too late (as an example I got drunk the other night with a few mates and on the taxi drive home the taxi driver was flirting like mad with me and yet I failed to pick up on it and was apparently really cold towards her... maybe thats because I was drunk though??)
Anyway, I think the answer is, talk to people and put yourself in those situations even if you get nervous and anxious about it because at the end of the day, you gotta talk to people and be around other people one day... so now is better than later!!