Hcg doubling time 71 hours :-/

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 some bleeding on and off for a week so doctor has been doing my bloods every few days , Monday it was 12,890 and today Thursday its 27,000 is this ok ? Or doubling to slow ?