I am on a different chemo regimen and the first week knocked me for a loop. I have 7 more infusions to go. The first night I got home I was considering stopping treatment but I made it through the nausea and fatigue and other side effects associated with my chemo agent.
I would speak to your nurse or doctor about the side effects you are having. There are many things they can do. Not being able to sleep is a common side effect of chemo and they can give you something for that. Even if you don't feel like eating, try to eat something even if it seems silly. I have had cookies for breakfast and pop m&m's all the time. Although eating healthy is important, eating anything at this time is more important. Your weakness will pass if you can start to eat something. Know that your food preferences will change. I don't buy a lot of anything even if I'm really craving it because sometimes by the time I get home from the store or the delivery comes, I'm not interested. Bland foods such as toast with butter on it helps a lot. Gatorade is good too.
Before discontinuing treatment, talk with your doctor and nurse and see if you can deal with the side effects. In addition, your doctor may be able to adjust your chemo so it's not as harsh on you but you can still get the benefits from it.