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This is most likely an abnormal cycle due to your early pregnancy loss recently. Since the uterine lining is not stable and your hormanes may be not quite back to normal, it's to be expected. Implantation bleeding is rare and occurs a few days before you expect a period. If at all. It sound as if your body is just getting back to normal
Yes it's ok to try. It's best to wait after miscarriage before trying. One month is sufficient. Risk of repeat miscarriage is about 5% higher if you do not wait.
Yes your next cycle should be fine. No worries.
If your pregnancy test is negative then you know that the pregnancy is resolved. There's no reason at all for a d and c. This is your period. Just a few days early.