Need help

Vivi
I was on birth control since August 30  i got it removed. I have my period sept and October but November I didn't got my period, December 2/6i got my period and on Sunday I blessed I gain n it went away quickly is it normal??? 
On Wednesday by accident felt down the stairs an I started bleeding. On November I did pregnancy test an it came negative I went to the ER and told me I wasn't not pregnant but I am ... They did lab test an confirm I had 119 hcg in my blood that means I was I conceiving berly the sperm to egg berly an told me it was a threat of miscarriage I'm so confuse ? Any help