Did your period make your supply drop?

I've been breastfeeding for 5 months and about two days ago I got my first period since I gave birth. My supply started to get low about a week ago and tonight when I pumped I hardly got anything. I did nurse my son right before but I didn't think he nursed for that long to actually empty both breasts. For those of you who got your period while breastfeeding, is it normal for your supply to drop like that and does it come back?