How Sun Manages Its Shape,as Many Explosive Reactions Taking Place Inside It?

In the middle of the sun, nuclear fusion takes place which release more energy than the hydrogen bomb. In outer space the one force that is greater than all the fundamental forces is gravity. As gravity pushes all the gases together it becomes so hot nuclear fusion occur. When this happen the energy from fusion couteracts the gravity in all directions. Just enough to keep its spherical shape. The fuel use for fusion is hydrogen and it produces heavier elements like helium and carbon, once it burns out of fuel, either gravity takes over and create a black hole or it goes in a huge explosion.