Hi t&j11106
As far as the pain in your mouth and throat, it should subside soon. Remember that the Radiation continued to " Cook " for roughly 2-3 weeks after your last treatment.
Do you rinse/ gargle with the salt and baking soda solution ? I often used that, just prior to eating because it semi numbed my mouth and throat. I also ate and drank everything at room temperature. The cold fluids seemed to burn worse than the hot foods. After several months, I was able to eat and drink things warmer and colder, it takes time.
As far as your energy level, I was told by my Oncologist that the Radiation stays in our bodies for roughly one year and it is a side effect to our energy. There will be good days and bad for awhile. This is kind of our new normal for awhile. Try to get as much nutrition in yourself as possible and some sort of exercise. It took a few months before I didn't have to take a nap each day after work.
My Best to You and Everyone here