Dear Tony,
Do the best you can.
Don’t strain yourself. Making these changes and trying things that you haven’t done in a long time (or never before) is enormously stressful. If you add to that by demanding that you reach certain limits, routinely do something at a specified time or for a certain length of time, you are going to burn out.
A large part of this is discovering what you can do, what your limits really are. People’s limits change from day to day (sometimes from minute to minute), are sensitive to moods and outside events, and frequently are not known in the beginning. People recovering from mental illness are even more sensitive to such issues. Your best work today may not be your best work tomorrow or the day after. Do the best you can at any certain point. Concentrate your efforts on not pushing too far and not burning out.