Hello I recently when to the doctors and the sonogram says I am 5 weeks. My last period was November 12. So according to that I should be 7 weeks. My problem is I had unprotected sex with my ex November 4. Could it possibly be his child? I was in the hospital November 22 and 24 and both time I went the took a urine sample and they were negative. I need help on an approximate conception date so I know my boyfriend is the father.