just wanted to give you some encouragement, i've struggled with dd eating/not eating, shes nearly 9 mths old so not the same issuses but i got some really good advise....look at the amount she has eaten over the week, apparently day to day isn't so important, is she going to the toilet/filling nappy (dirty and wet) regularly, and is she still sleeping well. babies know when they are hungry and i'm sure she'll let you know when she wants something. its good she has a sippy cup throughout the day as that would be a worry if shes wasn't drinking. i have also heard that from time to time children do seem to prefer to eat finger food than things off a spoon, this is definitely true of my nephew (13 mths). i was also advised to offer small amounts often...not too often though as if they are genuienly not hungry/off their food they will get fed up of being shown food!
i hope things improve soon as i know how frustrating and worrying to can be to see othe children eating and your own child isn't wanting anything!
do post soon to let us know how its going.