I think at this point I would put it down to recovering from illness and/or just going through a stage. If she is 'nearly' better I would guess she isn't all caught up just yet and won't be for maybe another few days, maybe a week. I remember every time DD1 got a tooth she would feed and sleep terribly, then the pain would stop and she'd be HUNGRY for 3-4 days and want to sleep lots, then get back to normal. I reckon every single time I would wonder if I needed to be doing something different, then magically it would fall into place and I'd go a-ha that was the issue!
If it is still happening in a couple weeks I would reconsider.