Survivor since 2007
The magic answer for constipation is MiraLAX. IT WORKS without the drama of other laxatives. My oncologist office told me about it.
As for appetite, your taste may have changed.... mine did, drastically. If course, everybody is completely different. What I ate sure isn't going to be what sounds good to you. I don't have anything that I could suggest as an appetite stimulous. I craved salads, spinach, anything green. I also ate "Hot Pockets" and we have chickens so I liked fried egg sandwiches. You can pick up some cans of "Ensure". It comes in all different flavors. It is like a little milkshake in a can. It is nutritious and recommended for people who can't eat solid food. There are also good canned soups that would be easy to fix the "Hearty" variety's are tasty.
Be sure to ask your oncologist, he/she might be able to suggest an appetite stimulous like vitamin B. I am sure they are used to dealing with this on a daily basis and will be of great help to you. Hang in there and hopefully you will get some good suggestions here.
Take care, Sharon