Period starts today

M

Hey guys sooo I know it’s still early morning but I am supposed to get my period today I haven’t gotten it yet and the last time my boyfriend and I had sex was almost a month ago and we used protection and no rips or tears and he didn’t cum so why could it be late?? Also after we had sex the last time I got a uti? So could that make it late too since I had to take antibiotics afterwards I’m just worried thanks