I exercised heavy yesterday for my bad condition. today my body is moderately sore (both legs, both arms and upper back). i also feel very tired/weak. urinating frequently (normal colour). could it be rhabdomyolysis? what to watch out and what to do?

It is more than likely due to your muscles being out of condition for the activity you undertook. Give it a rest for a day or two and start exercising at low intensity. Gradually increase the duration and intensity of exercise as tolerated. You may shoot of 80% of your maximal effort. Drink enough water daily so that your urine is mostly colorless. For healthy diet: http://www.choosemyplate.gov/