My husband just went through the same treatment. He also was so nauseous he couldn't eat. After 14 days of drinking water only (and losing 45 lbs), the oncologist finally ordered the feeding tube (peg tube). But at that point his levels were so low they had to build him up so he could have the surgery. That required a 5 day hospital stay receiving a blood transfusion, as well as liquid nutrition. He didn't receive radiation while in the hospital so this pushed his treatment back as well.
My advice, don't wait! Push your oncologist for the peg tube.
Good luck!