Sorry about your news. Mind if I come out of lurkdom to say something? If you're 16 something days past your period, you're officially over 6 weeks pregnant, not four (unless you don't have a normal cycle). They start counting on the first day of the last period.
If, at 6 weeks, you only have "tracable" hcg and no yolk sack seen on ultrasound, things are not looking good. But by all means, do have anther test done in a couple of days just for your peace of mind. Good luck to you, and all the best.
