What do you guys think?

So I am 37W & 6 days pregnant... I'm 18 my SO is 30 ... nearly every other day he Wakes up with some sort of chip on his shoulder... I ask what's the matter he says nothing or tells me to leave him alone... but when he talks to his friends he gets soo happy & excited ... I can't even tell you the last time I felt that kind of excitement from him when we talk... some people say it's the pressure of the pregnancy getting to him, so I thought about it but if that is the case why not talk to me about it? If anyone can relate it would be me right? The one going thru the phase with you considering that I'm carrying the actual fetus!? I ask pose various questions he either doesn't answer or says leave him alone... He rarely talks to me at all... yes we live together... he's the breadwinner of the relationship... I was in school but withdrew due to not being able to pay for supplies... considered working but didn't have transportation... he has a car but is stingy.... I'm in the house alone most of the time... sometimes I think he's cheating... although not certain... I have no proof... altho I did go thru his phone once around 20W pregnant & he appeared to be setting up a DA (dick appt) with a woman he used to fuck on but it didn't happen because she was busy... he said he didn't mean anything by it "he was just talking shit" idk but a lot of times ... majority of the time I feel soo alone. I love my baby so much already but in the same breath I wish I'd waited... went to school & grew a bit more b4 settling down & getting deep like this... I love my SO to pieces... but I'm not sure how much more I can take... I've been fighting for us hoping he'll eventually come around as well as trying to stay mentally stable for my baby as well... any advice?