35 weeks pregnant and im having pains?

im 35 weeks & 3 days pregnant and i been having sharp pains in my vagina. Me and my Fiance had sex 3 times in 1 day unprotected, they say they seimen softens up the cervix to induce labor but im not tryin to induce my labor AT ALL! Now im having back pains and dull pains in my lower abdomen and some pain in my thighs. WHAT DOES THIS MEAN?