Dee, I found that as the weight came off and I exercised more, I became stronger and more energetic. I am still a bit draggy now, but I am plugging away and trying to get back into a groove at the gym.
I, like you, had a major chest infection before Christmas. I was really close to having pneumonia but was too bullheaded to go to the doctor until a week before Christmas. The kids had come into town from college the week before and I thought I was "too busy." I have never felt that weak in my life, and it took me a good month to get the gumption to make regular gym visits.
I am telling myself it will take time and don't give up!