It sounds like twins or triplets to me. Those numbers are way too high for 6 weeks! Im 14 weeks with twins and mine were 1/2 of that at 6 weeks...
well because the numbers were increasing "normally" with the first 2 and the 3rd was less than 48 and still showed an increase... i think you need to see what the next numbers show... because so far the numbers are increasing, there isnt even a dip in numbers... so for now try to take it easy and not stress... just curious, is there a reason that they have been tracking your hcg levels?