From stomach virus to Ectopic Pregnancy

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I posted yesterday asking you lovely ladies for advice on my symptoms. I went to the ER yesterday as I hadn't heard from my OBGYN for two days and had my HCG levels checked and they are lower than they should be for where I am in pregnancy. I'm supposed to be 4 weeks and 5 days today but my levels are lower than normal for 4-5 weeks (4-5 weeks should be between 1,000 and 10,000 MIU/ML) mine are 808 MIU/ML. Plus severe cramping, dehydration, and no pregnancy detected during the ultrasound (transvaginal) they did. 
Needless to say, I'm scared and worried. I have to go to the hospital tomorrow and have a repeat test done to check my HCG levels which means another Quantitative HCG blood test. I'm hoping that whatever the outcome, I am safe and I pray that whatever happens is meant to be. I have two amazing little boys already. 
And I found out that I also have a uterine fibroid which can cause infertility and increase the chances of ectopic pregnancy and miscarriage. So hopefully everything works out. If not, at least I can be safe.