is he cheating?

Before I fell pregnant I never once questioned my relationship with my partner since I fell, I can't help but think he is cheating on me, he has fell for his colleague that he has now started picking up and dropping off from work, he hides his phone screen when texting. I really don't know whether it is me being paranoid as I'm not feeling too good atm, never mind looking good or if there is something there, whether me being pregnant is a total turn of for him or not, really can't stop over thinking it which in turn makes it 1000x worse. Has anyone else experienced this? Could it just be my hormones, or something more to it?