Same thing happens to me about 5 weeks passes a clot and had some bleeding. Went to the er doc did blood panel pap smear and ultrasound. They seem the sac but to early to see baby. Went back 2 days later they did the whole process all over again and my levels doubled and they seen the pole. I'm now 11w 5days with no problems. My doc told me if I wasn't having serious cramps and soaking a pad then I should be OK plus if you are having a mc there's nothing they can do to stop it. Good Luck
I had late implantation bleeding at 7 weeks, and it was very light pink and lasted a day but no clots. You need to see your doctor if you are bleeding bright red with clots, as though it is not considered 'normal' it can be quite common. I'd suggest some bloodwork for hcg levels and an ultrasound just to be sure.