Random sadness, and its taking over.. anyone else?

This whole pregnancy I've actually had no problem with staying at home and doing what I need to because I know it's for the baby. This last week (has been 23 weeks for me) has been the worst. All I wanna do is cry. My friends all smoke and party etc which I could care less about doing now, but I just have nothing to relate to them anymore and they can't seem to remember not to smoke around me and I'm starting to feel really rude to always have to walk away from a conversation every 20 minutes because someone has to smoke. And my bf he's either working all day or he will go hunting in the morning and evening which is basically all day. He tries to make a point of staying home once and a while with me but I just feel like I'm no fun and like once and a while isn't enough right now. I seriously just don't like going out in public anymore either to find something to do on my own. For example 90% of the stores/theaters/restaurants I go to walk-in someone is standing by the door smoking and it drives me insane that I have to walk through that when I've been trying so hard to be as healthy as possible for my baby... Idk this has turned into a rant but honestly I feel so alone and lost, I know I'm not and that my boyfriend and mom love me and will always be here for me but i just don't like feeling this way.. has any other mom to bes felt like this?