UTI infection in pregnant women - common?

I'm about 4 months pregnant and I think I have a urinary tract infection. I hate going to the doctor and antibiotics make me sick, but I'm about to give up. I am going to try an over the counter medicine - the stuff that makes your urine neon orange. I can't go twenty minutes without feeling like I have to piss fire and my lower back is killing me. I heard that since my uterus is growing and pushing on my bladder that it can block drainage and cause infections. Is that true?