When she wakes in the middle of the night and you feed her, does she seem hungry? Or does she just eat a bit and drop back to sleep? If she seems hungry, I'd feed her - maybe she's having a growth spurt. If she goes to sleep, though, I would try to continue with PU/PD to help her get back to sleep, so she won't learn to use a middle-of-the-night-feed as a prop (I made this mistake with my daughter).
I have a Spirited baby too, and PU/PD drives her crazy..... so I use shh/pat, even though she's five months old. It's very slow going, but her night wakings are getting farther and farther apart. I actually lie on the floor by her crib and shh/pat to comfort her periodically while she cries. Sometimes she cries more and more, but eventually, she settles back to sleep.
Good luck in getting some sleep
