Energy and Matter are interchangeable

at time zero the universe was pure energy. as time went on (a fraction on a second) the energy turned into very hot simple Matter. Over time, as this matter colded, it was transformed into more complex matter. The matter in you body was made inside a star. This transformation uses up energy.
The universe will continue to expand and cool. In the distant future our univere will be as cold as space 0deg K. At this time all of the energy from the bigbang will be in the form of matter. Nothing has been lost the law of conservation is still vailed. But the universe will not stay like this, it will change directions and start contracting. As it contractes, it speed will increase. It`s potental Energy will slowly change to kinetic. All of the matter will meet back at the center. The bigcrash will convert the matter back to energy. Space and Time will start over.