I’m freaking out !!

I’m kind of freaking out , I had sex for the first time in January and I did get my period the next week (after I had sex the first time) for 5 days ! This month I got my period with cramps and medium blood flow and it seems like it’s only going to last 3 days. I’ve never had a period this short and I do take birth control and I have been taking BC for the past 2 years and we used protection everytime and he finished outside of me. I’m really worried that there’s a small possibility that I could be pregnant just because my period is super short ! Should I be worried ?? I don’t want any kids rn ! Can first time sex mess up my period ?