You raise a great issue. You are at the "fork in the road" that I still struggle with-being the only sober one at a party of drunk people. No it is't very fun after 10:30 to be sure. Sometimes I leave early, other times I just tell myself drinking will make 10:30 to 1:30 fun, then I will feel awful the whole next day. There is no doubt this is a tough issue. I miss the party scene to be sure, but I enjoy sobriety 100x more. Keep going as you won't believe how good you will feel booze free....