I have had sex with my husband and I have a 7 month old daughter my period is 3 weeks late I should have started around the 13th of may and didn't I have taking a pregnancy test but it came up negative will my perido still be off since I just had my daughter in November

Had it been regular after it resumed postpartum up until this point? Several things can cause a period to be irregular after childbirth... the birth itself, breastfeeding, birth control choices, pregnancy, and just an occasional off cycle.

See what happens when your next period would be due for this month. If still no period, check with your doctor about having a blood test done.