thats really sad. i've felt that way, but from my own doing. i'm on the pre-op liquid diet right now and i was on the limited atkins type for a few weeks prior and when i went out, i felt a little out of place and even upset because i couldn't have what they were having... silly, i know! but no one else seems to mind! i have a birthday party coming up on sunday at one of my fav restaurants. when i told the bday girl about the liquids, she understood and even said that if i didnt feel like i wanted to go, it was ok. but not to worry about it either way. i decided i'm going to go anyway because i am going to have fun and talk and stuff with others. Even if i have to order water, put my crystal light in it and drink the broth from a soup there. the way my friend reacted makes me think that your friends are probably trying to be "supportive' by not tempting you by going out. but if you feel that you can go and still be faithful and have a good time... then i would definitely talk to them and let them know that you're cool with going and that you'll let them know if you feel like you dont want to.
good luck!