What to think?

I had mc and d&c sept 9th. A month later still no Af, this passed weekend little less than 4wks after d&c had some brown/black discharge for 2.5 days, (now nothing) & a little nausea in the evenings, not sure when I ovulated or when to expect Af. No other symptoms as of now. Could  tht have been implantation bleeding or just simply crazy spotting due to d&c