Help please

Lexus
Sunday afternoon I went to the hospital because I couldn't pee, had extremely bad back and side pain, a fever, and vomiting. They took a urine sample and said I had an extremely bad uti. Which was surprising because I didn't have anything wrong with my urine Thursday when I was checked. They also told me I was having contractions. They gave me antibiotics and fluids because I was also dehydrated. My contractions got worse, but then slowed down so they sent me home. They keep coming back but aren't consistent just really painful and it gets so bad I cant breathe. I'm 33 weeks 3 days. I have an appointment Wednesday with my doctor. My question is does this mean I could go into preterm labor? Also, I have no appetite. I ate nothing yesterday because it wouldn't stay down, and barely anything today. Will this hurt my baby? I'm assuming I'll get my appetite back in a day or two but I'm really worried.