Please Help.......

I just got a 9 BFP this weekend after TTC for over 3 years. But I have been having light pink spotting for the past 3 days. Called different Dr’s in my area and no one was able to give me an appt, so needless to say I ended up going to the ER. Well in the ER they did labs and U/S. HCG came back 691 but u/s did not show a sac. As per my calculations (based on first day of my last cycle) I should be 5 weeks) but the ER Dr said that my labs indicate anywhere from 2-4 weeks, no the no sac can be that I am either too early on or that I have gone thru a miscarriage. Now I haven’t had any bad cramps or heavy bleeding. I don’t know what to think. I want to be hopeful but at the same time can help but feel a little sad. As anyone been thru something similar and have had a positive outcome????