Stupid sad feeling

My fiancé and I are suppose to get married next month. We’ve been together for almost 2 years and its been the absolute perfect relationship. I’ve never been happier or felt more loved in my life. He has 2 of his own kids 1 lives with us full time and I had 1 when we got together, he was 18mo at the time and he’s been dad ever since. Biodad isn’t in the picture. We now have a 4mo together. Idk if I’m crazy or have some postpartum depression going on and it’s pushing him away or what but things have been SO different. We went from talking all day (I’m a SAHM and he works a job the normally he can use his phone) and now I barely here from him, and when he’s home just everything feels so different. I have this feeling in my stomach that just will not go away. I don’t think he’s cheating and he tells me it makes him upset that I think he doesn’t want to talk to me but I feel like he just doesn’t really like me anymore. I wish I could explain better but it just really sucks and I worry I’m just making it that way without meaning to and it’s going to ruin our whole relationship. I’m making myself crazy and I just so wish I could shut my stupid mind off. 😞