8 weeks & bleeding with cramps

I'm currently sat in A&E waiting to be seen. I'm 8 weeks pregnant and started spotting light brown on Sunday morning. Over the last 3 days this has gradually got worse. Today the blood is bright red and I have pain in my lower back and lower abdomen but no clots. I had a scan on Monday where they told me that the gestational sac looked good and the outer lining has thickened as it should but no yolk sac or baby visible.