Ferber method

So my babygirl is 6 months old, and she would not sleep unless I fed her to sleep (which would cause her to get an upset tummy cuz she wasn't really hungry) or I would have to bounce her continuously. I've been doing the ferber method for almost a week now and it only takes her about 20 mins to fall asleep on her own. But she still wakes up a lot thru the night and wont go back to sleep unless I feed her till shes sleeping or bounce her. Do I use the ferber method in the middle of the night when she wakes up too?