Does Bleeding Between Periods With Cramps Mean Pregnancy?

i am a 40 year old woman. Who has never had a child. My periods for the last year or two have been coming between 2 weeks to 3 weeks. I usually cramp 1 to 2 days before it happens with a sharp pain indicating it is here. I have had cramps for 5 to 6 days now coming and going. More going then coming. Could I be pregnant? What are the odds that I am? I had sex with my partner about 3 weeks ago unprotected. And he is suppose to have a low sperm count and can't have children.