Had unprotected sex on February 3rd. Took the morning after pill next morning and had my period at full length from the 7th-10th. I had unprotected sex again on the 19th Feb with no morning after pill. I am currently 23 weeks pregnant according to the ultrasound. Does this mean that even though I took the pill and still had my period I was pregnant?

If I calculate from the 19th, it's going to be 19 weeks, not 23 weeks. Please any ideas?

The failure rate of the morning after pill is low, so you could have been pregnant. If you run it back though the measurements lead to a conception date of 18th or so. The first two weeks is the time from start of period to ovulation.

Is there a reason other then curiosity why this matters?