PREGNANT MAYBE!!

Hey guys🙂. In abit of a scary situation. So on march 16th my boyfriend and I sex right before he left town on a job. We usually have this thing we do where after sex we pull the condom to check for any leaks, breaking etc. And everything was fine. Condoms work perfectly. Just to add. Unfortunately that's the only protection we use. Please don't judge. Anyways so I've having my periods when expected but my belly has slowly and grudually been getting bigger. But am not constipated and bowels are working just fine, no digestive problems. This month my period has been a week late and a few hours ago after I had a pee I cleaned myself and saw a thick blood spot on the tissue. Was really thick and dark red and just like that was gone. No bleeding and nothing on the second piece of tissue I used. I have no idea if am pregnant or this is normal and nothing's wrong. Anyone with any ideas what's happening? Really worried and scared