How to stop myself from crying easily?

this is my first pregnancy, an unplanned one. I get mood swings every now and then but this time round, it is so bad that I cry so easily for the past 2 - 3 days. basically I started feeling that it is so unfair that my lifestyle had to be changed so much. this includes stopping on smoking, drinking, eating raw food, & that big cut on drinking coffee tea coke, bbt and cold stuff. all these while my partner can just go on with his usual lifestyle. he tried, to not smoke with me. but everytime we go out with friends, it will be his cheat day. Well, we go out often. now I just want to isolate myself at home instead of watching everyone do everything that I wanted. how do I accept all these and stop crying? I'm really worried that my mood affects my baby.