uti experience

so i had sex on dec 6 and thought i might have a uti but brushed it off. my only symptom was going pee, having a little come out, and then having to pee again. finally after a few weeks i couldn’t take it anymore and went to urgent care where they prescribed me macrobid. i started to feel better and then a few days before i was done with the antibiotics the symptoms came back. i went to urgent care AGAIN and they finally did a culture to make sure they’re giving me the right antibiotic. the past few days i’ve been extremely nauseous and having some lower back and leg pain. are these part of the UTI or something else? i’m on the pill and had my normal withdrawal bleed so i don’t think i could be pregnant