I'm 19 days late and having migraines, but the hcg test was neg

I'm now 19 days late, and I was ovulating one of the times me and my husband had sex. I am also having migraines and that is normally my first sign I am pregnant, we already have 2 boys. My dr gave me a urine test and a blood test both of them came up negative last tuesday when I was 10 days late. It's now been 19 days and I still haven't started and started having migraines yesterday. I had orthoscopic surgery last friday, if I am pregnant will that hurt the baby? How much longer should I wait before I go back to the dr?