I'm having the same thing, it's all normal. I had 2 periods in 3 weeks, and then nothing for 50 days, so don't worry. just be cautious though ;)
However I haven't stopped breastfeeding, but it happens differently for everyone. Some of my friends only had it come back to normal after quite a few months
I agree, although annoying ...it is quite normal and may take up to a year to regulate completely. If it is really bothersome or you are ttc again, make an appointment with your doc as there are things he can prescribe or advise.