Help with hcg and scan pic

Kay

So confused hcg rising and nothing on scan just a small sac. Could it be too early to see and hcg rising from twins? Have i miscarried as i had some bleeding? Possibly ectopic but no symptoms that would accompany that? Anyone else have the same and things be ok?? I had expected my hcg to have gone down from the 16th confused if it was a miscarriage why it would have risen.