dumpy and frumpy

Emily
I have a medical issue that makes me excersize intolerant. I've gained about 15-20 pounds. I am 5'3" and weigh 140. I feel flabby and like I should live in a sweatshirt. I'm going to start calorie counting again but I feel more out of shape than over weight.     
Will sitting here flexing give me more tone? Or should I just workout then sleep? Or should I just invest in more sweatshirts?