help! NFP

hi everyone! my husband and I had a baby a year ago and have been using NFP. This is not for religous reasons but because i have horrible reactions to birth control. anyway, i wasnt supposed to ovulate for another week, but all of a sudden I showed all the signs of ovulation, including right lower abdominal pain tonight. we had sex last night. should I go and get th4e morning after pill? Having a baby for us wouldnt be horrible, but super unplanned. any suggestions? mostly Im just freaking out, because since my daughter ive had normal regular periods and finally have started losing weight for the first time since jr high.