I don’t know what to do

I lose feelings for my boyfriend suddenly I don’t know exactly why I did, but when he tells me he loves me and I say it back it doesn’t feel the same I don’t blush around him no more it’s awkward we arguing most of the time and or not speaking too each other I told him about how I was feeling and he was devastated because he loves me very much and it’s his worse fear to lose me, what he told me but I couldn’t believe it I don’t know why and I know you guys can’t tell me why but can somebody please try in help me understand why I could be feeling this way I’m also almost 7 weeks pregnant and us arguing so much makes me so scared.