I am going through this too. I know it is due to teething as she is showing the signs of it. I feed my DD laying down, or propped up on a cushion as she refuses to be held. If she takes about 3oz and refuse the rest of it, I play with her, change her nappy enough to distract her from eating, then 10mins later, I offer some more formula, most of the time she will take another 2-3oz, but if not, I resort back to playing with again, then try in another 10mins and so on. If she hasn't taken anything more within 45mins, then I assume she is not hungry enough. She is getting 3 good solids meals a day, so she isn't starving.