‼️‼️‼️HELP 21 yr old with UTI‼️‼️‼️

Can anyone explain why I’m getting UTI’s the exact same day my period starts for the last 2 cycles? Last cycle I started my period in the am and by night time I was having horrible UTI symptoms and went to the doctor for an antibiotic and it cleared up and I felt better. Now today I started feeling symptoms and I started spotting. My period is due 6/28 so I’m assuming the spotting is the start of my cycle. I’m not on any kind of birth control or any other medication other than cranberry pills (which I take to try to prevent this.) I plan to go back to the doctor tomorrow but I just wanted some input first.