How to get back in the game after being sick

I have been sick for two weeks and didn't feel up to my usual jillian michaels circuit training video. I've been taking it easy in hopes of shaking the cold. Also eating foods to help me feel better. More carbs an meats less fruits and veggies. Two weeks later I feel like my body isn't as tight. I still have a sick feeling in my sinuses so circuit training isn't an option. Yesterday I walked for an hour and felt ok. How can I lift to not lose all I worked for until my head feels clear enough to start circuit training again?