Had unprotected sex 11 days ago. took pregnant test yesterday morning.. neg. today morning pink spots than brown. could i be pregnant? period late by 5day

It's Possible: Yes, it is possible. Sometimes home pregnancy tests can give false negative results. You could do one of a couple things. You could wait another 5-7 days and test again at home, or you could go to your doctor and see if you can get a blood test to see definitively if you are pregnant, although those results may be more accurate in a few days too.