Hcg levels

Michelle • I`m 24 baby Declan arrived 08/07/2017! I have 3 angel babies.06/18/15 and mono-mono twins on 06/27/16.
So I got my blood drawn yesterday at 4 weeks 4 days at my Hcg levels were 918 she said they were low and that at this point she can not say I have a progressing pregnancy. When I look online and stuff it shows its normal for 4 weeks. What were levels then? Are my levels that low?