18dpo hcg levels ...

Michelle • 33 year old from Australia , currently pregnant with baby #4 a boy..miss 7 mr 5 miss 1 and prince due 26/01/17
So iv had to do the 3 hcg blood tests one each 48 hours , my levels seem way high and are doubling in 30 hours 
10dpo 48
14dpo 476
16dpo 1291
18dpo 3717