WHAT TO DO

So I slept with a guy while I was ovulating but it was my last day and the percentage of me getting pregnant wasn’t high. Do I need to do anything? I really don’t think I need to. We sometimes have unprotected sex. Things with him is a little difficult right now. We had sex one night while on my cycle and he threw up, since then we still have sex just not as often (like once a week, before that night it was more through out the week) and he’s trying to figure out if he wants a relationship with me. We work together too. So it’s weird to me, that we don’t say anything to each other at work, but when we see each other outside of work, he acts like himself with me lol.