Hello,
I really don't want to scare you but I've had 2 miscarriages and the second one sounds similar to what you're experiencing.
First miscarriage - Approx 7 weeks along, started with heavy bleeding early morning that did not let up, I was cramping bad in my back and going through a pad every 30 minutes. There was NO mistaking it was a miscarriage.
Second m/c - Also approx 7 weeks along, started out with very light spotting, then got brighter and slightly heavier but not much, I called the doctor who said to stay off my feet and call if the bleeding gets heavier. Well about 2 days later the bleeding got pretty heavy but still not as bad as my first m/c, about a normal period type of bleeding with some small clots so my husband drove me to the ER where they did some blood work and a sonogram and then confirmed it was another miscarriage.
I was so certain it couldn't be a miscarriage because it was SO different then the first, much slower with the bleeding, NO severe cramping or back pain so I thought it might just be implantation bleeding.....but I was wrong.
Now I have also had 3 full term pregnancies with 3 very healthy babies born so a miscarriage does not mean you will never have another child, or that there's anything wrong with you, it just happens to some people. And in between my two miscarriages, I had my 3rd child so they weren't back to back.
I'm currently pregnant with # 4 and have had some very light spotting early on in the first trimester but it didn't last long and was never heavy enough for me to even use a pad, it did scare me though because none of my other full term pregnancies did I even have any spotting but it can happen with some pregnancies and the baby still be fine. However if your bleeding doesn't get any better throughout the rest of the day, I'd go in to the ER or make a visit to your OB GYN and get your HCG levels rechecked.
Good luck, I hope everything turns out ok for you!