Pregnancy Timeline & Conception Date: Understanding Your Due Date

Question
Quick facts. I had sex (really nt sex just playing around by the area) with guy 1 last August 19th. Had sex with guy 2 from August 21st til Septembet 30th. My conception date is August 30th.But wrote before saying how i was confused because i dont remember getting my period in August.Even though the ultrasound on Sept. 23rd said i was 5wks 1day and the ultrasound on Oct. 26th said i was 10wks 1day.And just at my last ob/gyn appt. my doctor said i was measuring right. She said  ishould be 35cm but was 34cm. Could the ultrasounds be wrong? N if i had period July 22nd and went to the emergency room August 3rd because of extreme bleeding and was told i was pregnant bt my ob/gyn said i was pregnant bt had a miscarriage late july early august. Yet still ovulated around August 30th even though i didnt have a period . Does the conception add up? And if so Who is the fathet ? Please help because this baby is almost here and need to tell one of them.

Answer
Yes, the dates add up to man #2 being the father.  The ultrasounds are not wrong.  Early ultrasound between 8-10 weeks is accurate to within 3 days.  Just as I said before, you don't necessarily have another period after a miscarriage before you can conceive again.