Sometimes having trouble emptying bladder


I’ve never had a UTI so I’m not sure if maybe this is one but I’m finding I’m not always able to empty my bladder completely, like I can still feel more pee in there and if I sit and move around on the toilet sometimes more will come out. Last night was the worst it’s been and every time I walked to the bathroom I felt this sharp pinch in my stomach. The weird thing is that it’s so off and on, I was fine all day, emptied my bladder every time no problem, no pain except last night when I went 3 or 4 times before bed. I feel normal again this morning no pain and peeing normal. I have an appointment this afternoon I’ll bring it up but wondering if anyone has any ideas?? I’m 37 weeks today.