18weeks need advice

So I'm currently 18 weeks.. And I've gotten this weird pressure feeling in my vagina when I try to pee it feels like I'm pushing to hard and nothing comes out. I have the edge to pee all the time and when I do it's just a little bit .. I can't just willing go all the time.. It feels swollen but dr said it doesn't look that way at all. But when I really really need to go it feels like my bladder emptys at that time. No pain no burning anything dr told me could be pressure from the baby or uti.. It's not a uti or anything like that. . Any advice on what to do or how to help this ? Id like to pee normally .. Next step is if I don't feel for several hours I go to the er and they put a catheter in me to empty my bladder .. :(