IUD/bleeding after sex/ can't feel strings

So I had unprotected sex last night and I have an IUD. But I can't feel the strings and I am bleeding today (there was blood all over my finger when I checked for the strings). I went to the OBGYN a couple months ago to get my IUD checked because I couldn't feel the strings and it was there but I just have an uneasy feeling. I am 2,000 miles away from my OB and wondering if I should take a plan B or if I'm fine? I mean I would be in pain or notice if the IUD wasn't in place right? My period is supposed to come in 8 days so maybe it's early? Or is it a coincidence.