What Are The Ways To Confirm Pregnancy?

I am 38 yr oldwith A-ve blood group married for 5 yrs and trying to concive since last two years, last jan 2011 i was detected 4 weeks pregnant bt before my first routine check up i got missed abortion in feb 2011 (it was reveled during USG that though it was 8 weeks of pregnancy the fetous showd development equvivalent to 4 weeks only) then after certain test like thyroid and torch test i was given rubella vaccine in april before 10 days i found positive pregancy i.e on 21st oct 2011 but in usg no sac was seen, during follow today i.e 3 nov 2011 again there is no development seen , i was given hcg injection, and after 7 days again if there is no development the prgnancy will be terminated.