i'd be a bit dubious about your hcg results to be honest. they have detected a hb yesterday which is a strong indication of a viable pregnancy and your hcg level results are contradicting that.
What was your Hcg level on 5/26? Things could still turn around, but generally, when your Hcg levels don't double, and particularly when they fall, it is generally not a strong indicator of a healthy pregnancy. I wish you the best and hope things work out.