Not well versed in hcg levels, but could be a blighted ovum. I just had this last month.. the following morning after heavy bleeding I was told "no sign of pregnancy". But I know that I was indeed pregnancy, even if for very short time. I was 5 weeks. I am hoping for you everything is fine. And yes, it may be too early, and yes some pregnancies have bleeding and survive. But correct me someone if I am wrong, but should you not at least see a sac, yet? Could be they couldn't find it... best of luck.
one thing that i know for sure is , for 4-5 week been pragnant is too early to see anything , they can start to see the sac around 7-8 weeks , 4-5 weeks is too earlly , they could not see mine at 5 weeks either , but when i went at 8 weeks they saw it , i hope and pray for your angle to be ok :) best of luck