Nexaplanon and Unprotected Sex

Two days ago, I had unprotected sex (I'm on Nexaplanon) with with my boyfriend and he cummed on the outside of my vagina, I'm afraid that some went in though and precum went in. A day before sex, I ssyered having pregnancy symptoms and belly cramps, and now they are even worse. Anxiety is getting the best of me.. what do I do? I haven't had sex before so I'm freaking out more!