Are you alone at night or do you live with someone? Set up a hidden camera to see if someone is coming in when you are sleeping. Or fake being asleep maybe your freinds are ******* off on you.
If your with child, there may be damaging effects to the fetus, but this also depends on how far along you are and if there is a lot of bruising in your vaginal area.
One way to know for sure, go to the hospital and request a Rape Kit to be carried out on your body.
Wrap the sheets, blankets, and what ever you were wearing in a bag, the police will want to examine them. After you have taken the Rape Kit, the Police will be informed and carry out a search of your home.
But if you know you have no had sex, than there would be no reason you should be not come forward and contact the proper authority,