cramping after sex

My husband and I have been trying to conceive for about 3 years now, I have now taken my first round of Clomid. I am only 9 day past ovulation but my husband and I have had sex twice sense then and I have had extreme cramping directly following that I have never had before. I have not taken a pregnancy test yet afraid that it may be too early for an accurate reading and also afraid I will see a negative sign again. Has anyone else experienced this before and could it be an early sign?