Advice? HCG levels

Ca

So I went to the ER on Friday and my HCG levels were at 56, we thought I was about 6 weeks since we calculated the first day of my last period but on Sunday I got it tested again because they were worried I was either 4-5 instead of 6 or having an ectopic pregnancy and my levels for Sunday were at 256!! So they almost trippled! Any advice or any other women who have had that happen??