mine started up again at about 4 weeks. Same as you, really minimal B/loss up unitl that point. The all of a sudden it started up again for about a week - like a last whoo ha! It definately wasn't AF for me as I get migranes when i get AF and when I ovulate. I was pumping every 3 hours and didn't get AF back until kids started to wean off B/milk at 11 months. I certainly knew when AF came back as so did the migranes.

Ring you o/b if you are unsure, although you should be going back to him soon for your 6 week check up anyway, if I remember the routine??
good luck and keep on pumpin!!!
been there and done that. Any Q's just holla!
odette