This really seems to be a growth spurt. Combined with not feeling well or just recovering from a cold. I would still feed her on demand, sometimes it takes longer to up your supply, some growth spurts take even up to 2 weeks.
As for pumping, right now, she is working on your supply, everything you produce goes into her, that's why you can't pump really much. A few weeks ago we had a similar post about it. Actually, it seems that with a first child women may have an oversupply and tend to be able to pump much more. With a second one, their supply levels off and they produce exactly as much as their baby needs. Combine this with a growth spurt, you may end up being tied down by a hungry baby most of the time for a couple of days.
If you seriously worry about your supply you may try Fenugreek and Blessed Thistle, as Linda mentioned. These are safe herbs and were used over centuries by lactating women.