Help!!!

I’m 17 and I had sex for the first time. It happened the day after my period ended. He pulled out , no condom, and said we should be fine. Me being a nervous wreck took Take Action (cheaper form of plan B) within 3 hours. He also smokes weed so apparently that might lower the sperm count?? Idk but can someone let me know if I’m safe? I’m gonna start going on birth control but I’m not on it yet .