Great that you have a clean bill of health. I am sorry you feel dejected and tired - must be hard to deal with each day as it's difficult to look forward to things improving when you're feeling down. It must take a while for the body to recover from illness.
I know it's not the same thing, but I just went back to the gym after a month of fasting and it was demoralising to see that I didn't have the strength to do things I could do before Ramadan as I hadn't worked out for a month. I am going to try to focus on the improvements that will eventually come if I exercise regularly and try not to think about how much worse I currently am compared to a month ago. My health insurance gets me a free Starbucks and cinema tickets if I go to the gym at least 3 times a week, so that's one way of motivating myself to go, even though it's painful and not exactly fun. But I feel good after the work out. And it's really worked in terms of creating a habit of going to the gym regularly, which gives me more energy for other activities. I really enjoy walking as a result of the extra energy from the gym.
Maybe you could try promising yourself treats if you do something 3 times a week that will improve your energy levels and will eventually become a habit - e.g. a change in diet or change in scenery or through regular scheduled walks with a friend or through meditation or tai chi or a new hobby. I have to say I had a lot more energy when I stopped coming on this board to argue with people. It's nice to come on here and catch up with you though.