On birth control pill missed 2 in a row had unprotected sex then doubled up once then skipped a pill spotting off and on brown and red with no clots?

Unprotected sex: Semen remains viable for up to 7 days after ejaculation. If you had unprotected sex, you need to use emergency contraception. Oral contraceptive taken within 5 days of intercourse with the best efficacy within 72 hours. This is usually 2 doses, 12 hours apart. Effectiveness depends on timing - a dose taken <60 hours from intercourse: 4.0% pregnancy.