If you are having hot flashes it sounds like something hormonal to me. As joy said it can take awhile for your body to regulate itself...especially if this was your first child. For your own peace of mind I would consult your GYN. I've heard of women having to take hormones to balance things out and get their body back in the swing of things....
It can take up to a year for your body to regulate after giving birth. Your cycles may also become shorter, longer, last a longer or shorter amount of time, and have different flows than what you're used to.