I am like this too.
I can count the number of meals I have eaten the last 2 and a half weeks on one hand. I have absolutely no appetite. And on the rare occasion when I do, I can eat a few bites and get so full that I want to throw up. This not eating makes me feel extremely weak and tired all the time. I often get out of bed and go and get on the sofa and move all day because I don't have the energy to get up.