I accidentally skipped the pill the weekend of Jan. 13th. Slept with ex on Jan. 15th. Had a light period that week sometime but not sure on date, because of skipping the pill, continued sleeping with current boyfriend. Took a 5 day before missed period pregnancy test on Feb.27th, negative. Took another Mar. 7th, positive. Had an ultrasound April 10th and it said I was 10 weeks and some days. That would say conception was beginning of Feb. Due date keeps ranging from Nov. 4th-9th. Really worried about paternity of baby. Gut says it's current boyfriend but not sure. Please help!

Unfortunately, since you don't know the date of the period that month, you won't know for sure until the baby is born and a paternity test is done.

Chance are, if you only slept with "the ex" once, its probably your bf's due to the estimated time of conception... but it only take one time to get pregnant. Sperm, in a fertile environment, can live up to 5 days!

No way of knowing until a DNA test is done.