I'm 11 weeks and 3 days according to the ultrasound . when exactly did i conceive because on the 24th of july i started my period which lasted 7 days with a heavy flow and is confusing me because it doesn't line up with the amount of weeks.

Not too long ago: If the doctor says 11 weeks gestational age, or 11 weeks pregnant, then count backwards 9 weeks from the U/S scan date. If the doctor says 11 weeks post-conception, or conceived 11 weeks ago, then count backwards 11 weeks from the U/S scan date. The resultant date from counting backwards is the estimated date of approximately when the sperm met the egg (exact day is never known).