When I was 16, due to a very irresponsible pairing of an impetuous one-night stand and a few days of partying, I woke up one morning to discover I had mononucleosis and walking pneumonia. As if that wasn't enough, my period was late.
If you have NOT gladly and freely consented to and participated in sexual activity -- if you have not in some way said a big yes and wanted to keep saying a big yes -- and someone else had sex with you anyway, that is rape. No matter what ANYONE tells you, it is not your fault. There certainly is fault, but it lies with the rapist, not the victim.