I have breastfed my two children, and they were this way, and I realized - they were going through growth spurts. They did this at about 2 - 2 1/2 weeks, and again at about 3 months or so. It may have happened again at 6 months (I can't totally remember). The first time (after two weeks) was the most difficult - especially after my first because I didn't realize what was going on.
It took me about 2 days to get my milk supply to naturally keep up with her hunger, and then it was fine. I didn't do anything special (I didn't give her formula or any other foods), I just had to be a little more tired/patient those two days while my body caught up with her new needs.
I'm not totally sure if this is what you are experiencing, but the timing seems like it may be the case. I hope you are able to find out the help you need.
C.