Is it normal that i feel so exhausted?

Well me and my fiance have been together for a year and a half now. I also have a baby with him. Lately I have been getting stressed about everything in the dictionary. I'm getting to the point to where I'm just feeling so emotionally exhausted. We weren't fighting at all except when we first got together but now its been hard. And I know it's been me a lot of the time. Sometimes I'm just left feeling so alone and I don't know who to turn to. I guess thats where I'm at now. I get mad at him for the stupidest reasons and he blows up.. We love each other so much..and I want to stay together for the sake of the baby. I'm just stressed out about so many things,like whether my baby is gonna be healthy,pregnancy complications and all that.Our families also don't like eachother. I just don't want to lose him over me being stupid. But I can't help it lately..I've been so stressed and it's causing me to act this way. I'm also worried about going under high risk because of all this stress. I'm so caught in what to do. I wanna act right to him. I just want to know how i can keep this stress down and quit being upset all the time. I just want everything to be normal and safe with my baby.And I want to keep this relationship with the love of my life.

Sorry it's so long. I just needed to get it all out... Any advice???please?