I want to get preagnant but i dont know why i havent gotten prego?

So if my boyfriend *** in me the first day of my period can my period stop early?, until how many days can I wait to take a preagnacy test ?, I don't know why I got my period I thought I was suppose to be preagnant since he had c in me more dan 4 times , I'm not sure why I actually got my period if we even *** before my period , and I know you can't get symptoms early after but 2 days after I got heartburns ,felt tired,very sleepy, my started to hurt a lot , I had really bad pains in my left stomach . ? Why did I get my period ? ): I really thought I would be preagnant . , & can someone help me plsz I wanna know what's wrong ?, also I wanna knoe the exact days I ovulate if I get my period on the 25 th and I last wiff my period 8 days .