tschock is right the only way to confirm would be to go get your HCG levels tested. Usually though the blood color is your biggest hint on a miscarriage because it is bright red and not brown. When I had my miscarriage, I actually felt a "pop" inside and then I immediately had started spotting and it only increased until the process was over. Keep us posted, it would be good for you to get checked.
If it was a miscarriage the fetus would have come out while you were bleeding. By the way you have worded your question it sounds as if the bleeding stopped for 2 whole days and then something fell out...no blood with it.
When you have a miscarriage you normally have other symptoms to go with it...cramps, heavy bleeding, bright red blood, blood clots, shed lining ( looks like big pieces of skin with blood on it) etc.
It sounds like the period before this one is being compared to implantation bleeding...but I think it should have been shorter, not longer.
It's hard to say, but if you go to the doctor they can test your blood for hcg levels...if you had been pregnant it should show for a couple of weeks yet...your hcg levels drop after a miscarriage, but they should still be high enough for a week or two yet to tell.
Hope this helps.