UTI symptoms but no UTI

Krista
So I've had the symptoms of a UTI for about 2 weeks now has blood in my urine was put on anitiotics for a week but the culture at the lab came out negative? Went back 5 days after antibiotics were done still having symptoms they said I had a UTI so more antibiotics but the lab culture came back negative again! Went to the clinic today still have symptoms nothing showed in my urine..... I will be 4 months pregnant in a couple days and I CONSTANTLY have to pee I don't have trouble peeing no burning pain nothing just feels like pressure and like I'm not emptying my bladder fully even though I sit on the toilet for like 15 minutes to try and empty it completely. Could it just be pressure from the baby? Anyone else go through something like this?