Bleeding clots and cramping badly

I went for a scan a week ago due to some bleeding and I thought I was 8 weeks but the nurse thinks I could have my dates wrong. but baby was measuring at what looked like 5 or 6 weeks. had to have a vaginal scan to see if we could see a heartbeat but the nurse 100% if she could or not. I looked and I couldn't really see one either. since I've had bleeding that's just a little lighter that a period but only really happens when go to use the toilet. but there have been some tiny little clots and having some really bad cramps on a night time but I'm okay through the day. I have to go back a scan on the 3rd and see if there's any improvement on babies size and if there's a heartbeat but with the cramps and clotting I'm guessing there's not going to be much