Help spotting 6 weeks exact

So I had blood work done last week my hcg more than doubled in 48 hours it went from 2,500 to 8,000 I’ve had severe morning sickness and nausea all day for a few days I’m 6 weeks exact but today I noticed this morning I had brown spotting in tissue it went away don’t have cramps or anything and I went to the bathroom and seen a little brown spotting again .. I haven’t had sexual intercouse in two weeks and I’m not sure what this is I’m worried about a miscarriage :/