My period is late 😐

My period is now 6 days late and I've taken two pregnancy tests and both came out negative. I've been having extreme cramping, constipation, and have been suffering from a really bad uti for the past 4-5 days. I don't have insurance at the moment so going to the doctor's is out of the question and I'd really like to refrain from going to the hospital. Any ideas as to why my period is late?