Iam really sad, how do i change that?

There are a variety of ways you can make yourself feel better. Indulge in a hobby that you enjoy, or if you used to enjoy it but you haven't done it in awhile (this can possibly* be a sign of depression) try to get yourself to do that thing again.

you can also listen to music, exercise, draw, or paint your feelings.

there can be many activities that a person can do for five days a week for 60 minutes.

one of them can be playing football or any sport you love because it can you get better physique as well as strength and stamina also not so tough to play for 60 minutes.

another activity can be swimming which is really good for endurance and stamina. it goes and hits up all parts of the body muscles from feet to hands. so it quite recommended by doctors.