Bladder

I'm pretty sure I don't have a bladder infection because it doesn't burn and nothing hurts.  BUT! When I go to lay down at night, it just doesn't feel right, it feels like I should go pee even tho I don't have to.  It's only at night when I lay down to go to sleep.  I'm only 5.5 weeks preggers so my uterus can't be pushing on my bladder already...right????