Well, here's the real question: Have you had sex since you miscarried in April? If "no", then how in heck could would possibly think you might be having implantation bleeding in September - 5 months later? You wouldn't even still BE pregnant 5 months after having a miscarriage..
Besides, you began a menstrual period on August 30, which is BETWEEN the time you had a miscarriage and the time you now think you are having "implantation bleeding". You KNOW you weren't pregnant at the end of August, because you had a period.
"Implantation bleeding" (or spotting) doesn't last for 7 days - it only lasts for about 24 hours. For you to be having "implantation bleeding" in September, you would have HAD to have sex AFTER August 30, and an egg would have to have been fertilized during that time..