Not feeling well

I haven't been feeling well the last couple of days and this has severely restricted my food intake. I am not sure if it is something in particular I am eating that is doing this, or just my diet. I am going to the doctor's office next week so they can check it out but in the meantime I am barely eating anything. While it does seem to be working, I am a bit concerned about how much energy I will have over the weekend for a backpacking trip with at least 5 miles each day. The last day is 2 miles back to the car. I am trying to plan what meals and things I can eat and I have decided to go with plain things like mashed potatoes and homemade granola bars which I have been eating during the last week with few issues. I have decided to do a radical change in my diet after the doctor's visit. I kind of hope they find something so I have something to work with, but I fear they won't.