I know things can get crazy! Just try to take some time out for YOU every day! Soak in the bath, read a book, do things you enjoy that you wont have time to do when your baby arrives! I'm sorry your bf isnt very understanding or sympathetic... Them being guys I suppose it's hard for them to understand what we are going through!
If sex is becoming too uncomfortable for you than just don't do it! If he can't understant it then too bad! You and the baby come FIRST! I hope things calm down for you or at least mabey after the weekend things will slow down a bit? I hope this helped! Good Luck and happy holidays!