Took plan B and missed my period

So, I had unprotected sex on Jan 4th (the day after my ovulation date although that may not be completley accurate I'm not sure), and again on the 6th (yes, dumb idea) and I took plan B very soon after. Yesterday I was supposed to get my period, hasn't happened. My boobs are really tender and I've been nauseous and I'm kinda bloated and I've been experiencing PMS-y symptoms but I'm still not sure what to do or think... Please help :(