I would say you should stay calm and rest for a while till the time you feel you are perfectly fine and can start working out. But if you really feel to do some exercise you can normally just have a walk for about
30- 45 mins which will make you feel fresh and energetic. You can also add some natural diet supplements to your diet which increases your metabolism and helps you to stay healthy. When my friend has a surgery she was suggested with natural diet supplement, you can
try these out or visit your doctor for a good suggestion of supplement which will suit your body.