am i over reacting?

I feel as though my partner isnt interested in me anymore.. he barly speaks to me, is constantly on his phone doing god knows what.. we used to be extremely close and he couldnt keep his hands off me, now its a different story, we sleep on separate sides of the bed, he hardly cuddles me, doesnt kiss me and isnt interested in sleeping with me at all, we argue over the stupidest crap imaginable.. its like when we found out we were expecting he lost all his feelings for me.. and i dont know what to do anymore, i love him and we were engaged but now i just feel like im alone and living with a stranger.. like i said hes always on his phone, he never checks his inboxes while im around and always has his phone on him like he has something to hide... am i over reacting and letting all these pregnancy hormones take over??... i try and talk about it and ask questions and he just gets angry, shuts me out and turns it onto me.. any opinions would be great.. 
thanks...