She is probably getting ready for a growth spurt. Take her to bed with you, and make sure your breasts are available so you don't have to really wake completely up when she latches on. (Don't worry, she'll find the breast.) This will pass quickly, and you can get back to the normal patterns.

A book you can read on the subject is Tina Thevenin's The Family Bed http://www.amazon.com/exec/obidos/ASIN/039952729X/qid=1104872082/sr=2-2/ref=pd_ka_b_2_2/102-5443276-6772143 (There are other books on this subject, but that's the one I read when my son was tiny.)