Plan B reaction?

On the 14th of January (now 16th) my boyfriend and I had sex and he pulled out for a sec because he heard a noise and he saw the condom was broke. Just to be safe I got a plan B pill, I took that yesterday the 15th. I woke up this morning and nearly passed out in the shower, which happens to me occasionally. I got out and sat on the toilet so i wouldn’t fall and I got really nauseous and was gagging but not throwing up. I got a really sharp pain on my left side, like something burst but not my appendix because wrong side. Could this be a reaction to the Plan B pill or just nerves from being anxious? This was around 6:30 and it’s now noon and I went back too sleep and I feel okay now.