hcg levels

Tq
I'm really anxious to know if I will have twins. My first pregnancy was a vanishing twin so I'm curious to know early if I conceived twins again.. I had an ultrasound at 3 weeks 5 days and it was too early too see anything then I had blood work done at 4 wk 1d and my hcg levels were in the 300's .. I'll go next week to check again to see how much it doubles😬
 anyone else have these levels at 4weeks??