Has anyone had recurring UTIs in pregnancy?

I’m 20 weeks pregnant today. In December, my urine test came back that I had a UTI. I took the prescribed antibiotics (Macrobid).

In January, I developed crazy awful UTI symptoms. I went in for another urine culture, and it came back positive for UTI (again). I took the prescribed antibiotics (Keflex).

I went to the OB last week, and SURPRISE, my urine culture came back positive for a UTI (again, again). I’ve never had a UTI before getting pregnant, and I’ve never used medicine (including birth control) before these antibiotics. I’m worried three rounds of antibiotics are going to hurt my baby. I drink cranberry juice and aim for 15 or more glasses of water daily. I’m not sure what I’m doing wrong, or why it won’t go away.