I have gotten something like this, maybe it's the same thing.
In the first few weeks, I would sometimes notice a CRAZY bad headache HIT ME like a ton of bricks, while nursing. I guess it was hormones moving around. Sometimes some depression or irritability would hit too while nursing, even now at 4 months.
I have had depression, diagnosed as bipolar II at one point, and also have OCD, have experienced general anxiety too in my life. Right now it's not too bad, though, and I am not on medication. Things seem to ebb and flow throughout different phases of life and I am managebale.
Then, while pumping (which is something I do very rarely, because I hate it) sometimes I would all of a sudden get SUPER super irritated. I would feel it wash over me. Almost like the irritated side of PMS, where I diss something unnecessarily, and some poor chap has to hear it..... but to the extreme. And by the time I was done pumping, I would be like, "why do people do this? Such a waste of my F'ing time....etc etc." It would make me kinda hostile. I think it was that overstimulation, forcing that many letdowns. So pumping took a symptom of breastfeeding I'd get, and make it more extreme.
Sometiems even now, I feel that wave wash over me while breastfeeding, where my personality just changes. I just roll with it, because I am "Not" giving my baby formula, and it's not so bad, I am able to deal with it.
In my Mommy and Me class, I mentoined it, and one other woman who pumps exclusively said she gets that WAVE of depression that hits her while pumping. So I don't think it's tooooo uncommon. No one else said they had it though. Good luck!!!!!