Hi! Welcome po sa community! Honestly, it's really hard to tell this early, a week after sex, most pregnancy symptoms haven't kicked in yet kasi the embryo is still traveling to the uterus, so what you're feeling is likely PMS or just your body being extra aware because you're anxious (which happens to all of us!). The most reliable way to know talaga is to get a pregnancy test around the time your period is supposed to come, kaya patience lang muna while you wait, a few of us tried testing early din and nag-waste lang ng tests haha. In the meantime, if you're worried about the withdrawal method not working out perfectly, that's totally valid, so maybe chat with your OB about your options para sa peace of mind next time? Sending love, at welcome ulit!