Hcg levels only 13?

Hi everyone...I am somewhere between 3-4 weeks at a guess because I'm not actually 100% sure when I ovulated exactly. Going by flow I was 10dpo yesterday though. I had tested 9dpo and got a negative then tested yesterday at 10dpo and I got a vfl on a test and went to have bloods to confirm. The nurse rang me today and said she got my bloods back and my hcg level was 13 which she seemed OK with and said to go in to see my Dr next week after actually missing my due period etc. I'm just wondering though has anyone had hcg this low and gone on to have a healthy pregnancy? Or should I probs be preparing myself for the worst?