My boyfriend and I had unprotected sex on the 18 at like 2:00 am, he didn't finish inside of me though. But that same day I started my period (in the evening). I've been feeling nauseous and had to run to the toilet because I thought I was going to vomit. I also have been urinating more frequently along with a bit of constipation. I read online that some people said you can still have your period after conceiving and before implantation. I mean I honestly don't think I'm pregnant, I'm thinking maybe it's new period symptoms (I'm hoping) but I'm just wanting some inputs on the situation. So tell me what you guys think and if these could potentially be period symptoms???