I had sex with my SO on the 7th and I think I'm most likely going to get pregnant. I'm supposed to start my period tomorrow but I heard that it's possible I might not even get it if I am pregnant. Even if I do I might still be pregnant though and I'll probably miss next month ? I just want to make sure this is true , also, when would I be able to take a pregnancy test ? Like would me being on my period affect the test in anyway ?