16w pregnant and my bf seems to hate me?

okay so ive been dating my boyfriend for about 9 months now. he has an ex wife(not really ex, they are still married) and two kids with her. and about four months ago we found out i was pregnant. it was a huge shock at first but he couldn't have been happier. we both want a boy so bad, i always have and he want a "jr" ha ha. but anyway, we've had our bumps along the way ( hes two years clean off dope and just got out of prison when i met him) so he has a hard time dealing with normal issues of life. but he was really making progress. we were happy. but we live with my mom and we really need to get our own place, i had a job but he just broke his leg and is trying to work through it so he can work. i know its very stressful, he feels he is supposed to support me and the baby but he cant. im now almost five months and i was looking for a second job but having a really hard time, i finally got one and he took over my first job (the type of job allows it) so i wouldn't have to over work myself. well now hes been doing it(a night job) and hes not getting much sleep. and my job kind screwed me over and hasn't called me in almost a week. so once again the stress is coming on as we need the extra money so we can get our own place before the baby comes. but just recently hes been so angry and it always seems to be directed at me. hes just been so grumpy and mean. always telling me im doing something wrong, when i voice my concerns about being a "whale" he just laughs at me. and every time one of those like child abuse or abandonment commercials comes on he tells me "you better not do that" as if im watching it thinking-thats a brilliant idea!!!- and ive been stressed out and sad anyway(hormones) so this just makes me break down. and he seems to have no idea why. so tell him how much the stuff he says hurts me and he seems to understand and apologizess. but just today. i go to take his mom to the doctor so he can sleep in some and when i get back hes just grumpy all around. he doesn'tt say anything but just his attitude is bad. then he starts making fun of me for being in a mommy support group on a social site which, of course, hurts my feelings. i lay down to stretch with him(physical therapy for his leg) and as soon as i start stretching he tells me oh your doing it wrong. i kind of snapped and said "would you just let me do it? " and he got up in a huff -"well f you then blahblahbalhh" and he called his buddy to come pick him up....i asked him what his issue was and he said all this!(meaning our living situation) so i asked him why he was takingg it out on me he couldn'tt give me an answer and now hes wont talk to me. so i guess my question is, WTF?! why can i seem to keep him happy? why is everything i do wrong? why does he seem to hate me these days, and WHY, if hes so quick to get our own place, does he NOT help me look? im super stressed about this and im already worried that somethingg is going to hurt my baby. i justdintt get it. thanks guys. and im really sorry its so long.