Baby not eating

i am going through some really rough days.... my baby use to drink 26 to 28 oz per day plus solids since the last 3 days his apetite completely changed.... i have to throw his bottles half filled now he is taking not more than 23 oz with a lot of struggle i am trying to feed him round the clock so that he drinks something... on the other hand he is taking his solids without any effort 2 oz fruit puree in breakfast 2 oz chicken with veggies in lunch and 2 oz chicken stock in dinner (this is the same quantities he was taking previously)...