There is nothing to worry about for you. You need not rush into anything as there are side effects to every medicine you take.
Continue with your lifestyle modifications, do moderate physical activity everyday and then increase gradually.
As you'll begin to build muscle, your physique will begin to grow accordingly.
Health Tips
You can add protein to your diet in form of supplements and/or health drinks. They are the building blocks of the body and help to build a better physique when combined with physical activities.