Pregnant with Skyla?

I've had Skyla for about 8 months and it's been great. Except earlier this month, I had sex with my boyfriend when he wasn't wearing a condom, and he ejaculated inside me. At first, I knew that the IUD would have my back. Then I started to feel really shitty, almost like I was pregnant. The weirdest part is that this happened at a point in my cycle before I even ovulated... So, taking into consideration that it was 2 weeks pre-ovulation and the fact that I have an IUD, could I be confusing PMS & pregnancy symptoms? Feedback would be great. 

Thanks!