hcg levels


I had a blood test done Monday morning my hcg was 302 then another this morning, because they are being cautious because my last pregnancy was ectopic, my levels this morning, Thursday are 1173. They said my blood work is saying I am about 6 weeks but I know i am only about 4 and half. my question is. is that good that my levels went from 302 to 1173 from Monday morning to Thursday morning. and if so why is it a level saying 6 weeks when I know i can only be about 4 and a few days?? sorry freaked out because last pregnancy was ectopic and had to have emergency surgery.