What do you do when nobody excepts you?

i have stopped drinking and smoking. i wanted to stop before it became a problem for me to stop. and now none of my friends include me in anything they do because alls they do is drink and smoke. they feel uncomfortable around me because im sober. i miss going out terribly and i dont mind being around it even though i do think they all have problems (like addictions) my boyfriend drinks and smokes as well and he goes out with them all the time. and it really upsets me. one of these people is my best friend... or used to be at least... this is one of the main reasons why it upsets me when he goes out with them. i feel like i would have to start drinking and smoking to ever be part of the group again and that is not fair to me (i wont do it) i have told my boyfriend how i feel about all of this and he feels really bad but still goes out. and i feel really bad because i dont want him not to go out with his friends. i dont know what to do im really lonely and depressed