It sounds normal to me. It sounds like she is trying to connect with you after a time away, which is normal, because nursing is such a comfort to young children. Toddlers of this age seem to get really attached to nursing, or perhaps it's just my perception. It seemed like just as I was thinking they would slow down on it, they'd nurse even more, perhaps perceiving that I was tired of it and wanted it to stop, which made them cling on all the more.
Especially at night, it seemed like they would wake up more than when they were babies! If you are getting weary of nursing her all afternoon, you can try to substitute other means of connecting. I remember my daughter coming to me when she was three, asking to nurse, and me saying, "awww, you seem bored, do you want to play a game?" And she really was bored, and just wanted me to do something with her. In any event, the immunities in breastmilk are even more concentrated, and maybe with all the experiences of the toddler program, she just really needs to come back to you for all the warmth and comfort of nursing...and if she's getting sick, she might nurse more then as well.