Possible miscarriage?

For the past 4 days j have tested positive at home for pregnancy. According to my last period I would be close to 5 weeks right now. Yesterday I was cramping heavy and starting bleedibg bright red. ( I have heavy intense periods and this feels and looks like it). It started off light not touching the pad just there when I wiped l. Now it's heavy and some clotting. I went to hospital and they tested me at an hcg level of 26 so I'm going back Monday for another blood test to compare the results. If it doubles I'm having a good pregnancy so far, if it lowers I'm miscarrying. I hear you can't bleed like this with the heavy cramps and clotting and still be pregnant. Any thoughts?