Looking for some peace of mind

My boyfriend and I had unprotected sex on the 31st of December. I have been on the NuvaRing for about a year now and he pulled out but I will still worried so I went and took Plan B. I was took this on the 1st of January and was supposed to be ovulating around the 3rd-5th. I am only 17 and my boyfriend and I are both planning on going away to college so I really would not like to be pregnant. I keep going through my head of worry and then thinking I’ll be fine but I just wanted to get a second opinion! Thank you!