Someone pls help.

So my boys mom is scared that me and him will get prego. Welllll I’m 15, 16 in a month and he’s 17. He cum shotted on my vagina on accident. I’m on birth control (the pill) and we bought a plan B pill the same day just to be safe. But I was on anti-inflammatory pills for a minor injury so idk if that cancelled the birth control and plan B pill out. We took a pregnancy test like a week after and it was negative. I honestly don’t know what to do. I haven’t missed a period yet but I’m really close to when I’m supposed to be starting. Idk what to do.