Pregnancy levels...

So after two miscarriages my dr decided to put me on progesterone. Yesterday (at 4 weeks, 2 days) I had all of my blood/urine testing- my HCG is 663.8 and my progesterone level is 28!! Everything else looked great too!! This is still pretty early on- has anyone else had such high levels of HCG so early? Twins run in my family, wondering if it could be possible!!!! I won't have my first ultrasound until September 30th... So hard waiting!!!