Don't feel guilty if your health requires you to cancel out at the last minute. Let them know that it meant a lot to be included and you would like to be asked along again. If you are too fatigued to go to a movie theater, but would enjoy some company, ask your friend over to watch TV instead. Socializing balances the feeling of isolation. Whenever you plan an activity, discuss potential problems.
Contingency plans provide alternatives if problems arise.
Taking risks can be stressful, but careful planning and preparation will reduce stress and make activities more enjoyable. You are usually the best judge of when to stop and when to keep pushing. Always stop before you feel exhausted. Begin to be health conscious about such things as diet and reducing stress. Contracting CFS should help you learn to take care of yourself in a healthy way.