Dear OrganicMimi

Muscle weakness is common side effect of rapid weight loss and regaining weight does not naturally mean you will regain the muscle. All exercises are graded and  since you don't have the energy and endurance to  start an aggressive program, a good option for you would be to get a Physical Therapy referral to learn a home exercise program. A Physical Therapist will be able to test your strength and endurance and start you off at the right phase of strengthening exercises with advice on how to progress. This requires no more than 2 to 3 sessions and if you are a good student, maybe less.  Remember, strengthening can be done in many ways. If you are medically allowed, pool therapy  or water aerobics is a great way to start your journey. Another option is yoga, where you can begin the process of stretching and strengthening. If you like gyms, they have a wide variety of classes at many levels. Here, you can do as much as you can and just sit out the rest.

Hope this helps.