Often people that exercises might get injured, regardless of the type of physical activity. Time ago I stretched the posterior tibialis (calf muscles) during a Barre class. Considering that even the minor injury is annoying but if you add fever and sore throat, it gets’ really annoying. Especially after debilitating influence, your body becomes your worst enemy. How to get back in the game quickly? The recovery is always difficult and frustrating because you lose days, weeks and you lose muscles tone. It is said that to recover the same strength / muscle tone that you had before the break / injury must be twice the time of the break itself. (Of course if the injury is serious it might take much more). So if you stop 2 weeks, it takes a month to return as before. At this point there are no magic potions (for normal people, athletes are another thing) one has only to arm with patience and determination to work every day.
You need also to ask yourself what the body wanted to tell you? Sometimes we get sick or injured there are physical body imbalances and mental stress due to external agents. We should be receptive and maybe change something in our workout/diet/lifestyle.

What to do:
Making sure you get the ok from your doctor/physical therapist to get back, start with the stretching.
Be in control of the body gradually, maybe taking a restorative yoga class, this is a moment to be nice with themselves. Choose the right exercises for your level in this moment and be consistent with the exercises recommended by the PT in the case of previous injury.

Food choices. It is obvious that the food is our power and for the different nutritional values of certain foods over others, then start with a heatlhy diet for a healthy physically and mental recovery.

Back to your workout routine by reviewing the number of repetitions and level of difficulty. Which means that if I normally practice Pilates for an hour, maybe I’ll start with 30 min, or 1 hour taking some breaks in between. You don’t need to further stress more your muscles.

Switch the work out (but his is a rule that I always find ideal), today Yoga, tomorrow hiking, then Pilates etc., alternating cardiovascular exercises with resistance and strength.

Day after day, your energy’s level will improve and so your muscular tone.