Please help

Ok so me and this guy like have been messing around and we didn’t use a condom this time. I know he didn’t precum in me cause it when in my mouth and he didn’t cum in me cause some almost walked in on us so he pulled out and never finished but I’m 2 days late but my last period started on the 26 so I’m wondering if that when I will start this time. And my days aren’t always right but I’m kinda freaking out and I need to hear y’all’s opinion about it