On October 29,2016 @4 am I let a guy stick the tip of his penis in my vagina and he had precum and tried to go in my vagina further (I am a virgin). He urinated before this happened and had been consuming alcohol. It was annunprotect encounter(no condom). He only stuck in about three inches. I was scared and purchased and took a plan b at 2 or 3 that afternoon. I got my period on 11-6 about a week after taking the pill. I'm not sure if it was the pill, or my period ( my scheduled period was due on 11-10) my period was through on 11-11. I hope it was not implantation bleeding. Could someone help me because I really don't want to be pregnant and are there any STD risk, he didn't feel like he had any bumps on his genitals ,it was dark so I couldn't see. Any pregnancy risk , did the pill work , any STD risks?