At my first ultrasound on aug 7, they stated i was approx 8 weeks. what week period would i have conceived? if i had sex in april would that have caused the conception?

No, too long ago: If the doctor says 8 weeks gestational age, or 8 weeks pregnant, then count backwards 6 weeks from the u/s scan date. If the doctor says 8 weeks post-conception, or conceived 8 weeks ago, then count backwards 8 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 (not able to estimate a exact date).