Unfortunately right now it is too early for you to really be sure either way. I've had 5 pregnancies, 3 ended in miscarriage, 1 resulted in a healthy, lively now-2-year-old and I am currently 4 weeks from giving birth with number 5. I bled in all 5 pregnancies, all of them in the early stages, and all were similar levels. With my 2 full term pregnancies it was implantation bleeding, with the other three (all before 12 weeks) unfortunately it was a miscarriage. The main difference between the two (and this may be tmi) was the presence of clots for the miscarriages, but not all women have this.
It is the hardest thing in the world to do right now, but, unless you get significantly heavier and need to head to the hospital, about all you can do is sit and wait. Rest is absolutely the best thing. Don't take more tests - the pregnancy hormones in your system will still be there for a few days even after a miscarriage.
If it is the worse case scenario, then just remember that there was absolutely nothing you could have done to avoid it, you could not have prevented it, and some pregnancies are sadly just not viable. You will be able to try again soon if you want though. Speak to friends and family, and there are other support groups out there if you need. Miscarriage is still such a (wrongly) taboo subject for some reason, but the majority of women I know who have been through pregnancies and have had a healthy birth have sadly experienced it. I'll be thinking of you. x