AF Returns, again?

I'm wondering if anyone can provide any insight as to what on earth my body might be doing. :confused: I am 7 months post partum (normal vaginal delivery, no complications) and I bled off and on for about 8-9 weeks after. :( I also had some light bleeding for about 3-4 days around 4 months post partum. AF truly returned for the first time in mid-June, complete with cramps, oily skin, break-outs, mood swings, etc. Bleeding was HEAVY but lasted my usual 7 days. About 2 weeks after that ended, I got a yeast infection. :( This is not uncommon for me shortly before AF. And a couple days after the yeast infection, I started to bleed lightly. This has lasted now for 6-7 days. (Sorry if the math doesn't add up quite right, I haven't been keeping real careful track.) It does not seem to be getting heavier or lighter - just steady, dark red bleeding.
What do you think? Is this another AF? Breakthrough bleeding? Something else? Should I be concerned? I am not taking the pill, or anything else for birth control. I am still nursing my baby 4-7 times a day. Before this baby, I usually had an irregular 45 day cycle.
Any thoughts or advice would be helpful! Thanks!