How to get in a good shape?

Do strength training and eat more calories! Just make sure while you are doing your strength training you eat more. Just google "strength training for women" there will be enough result there for you to find something that will work for you including videos.

Best wishes

If you are underweight you should speak to a nutritionist or doctor about how you can gain weight safely.
Any exercise will improve your fitness. If you are eating right and not overdoing the exercise then you will not lose weight especially since you do not have excess weight to lose. Exercises like swimming, weight training and martial arts will help you to improve your fitness whilst also building muscle.

Lift weights and eat more. Please don't google "strength training for women". Most lifting routines targeted at women are ineffective. Good routines for beginners are starting strength, stronglifts and strong curves.

Then swap fat for muscle. Muscle is denser than body fat and if you develop more muscle tone, you'll run better and will maintain or increase your weight.

You're grossly underweight. You're tired because you're not giving your body the food energy it needs. Running is cardio.. Cardio burns fat.. this is how you LOSE weight.

Quit running. Start eating and strength training.

Come on over to my place and I'll show you some short cuts to shape you up.