According to the data sheets on Tri Sprintec you should be certain you are not pregnant.
Tri Sprintec can cause birth defects. Although studies bring this point into question showing that the occurrence of birth defects is extremely low the birth control pill carries an FDA X value.
I would retest and if you were to miss a second period it is recommended that you see your doctor. I myself would contact a doctor now and have an inclinic pregnancy test done.
Wishing you all the best,
anil
From the husband who has done a great deal of research on this birth control option for the wife he loves very much.