Why does Juliet kill herself after she wakes up from being drugged?

When Juliet wakes up from being drugged, the first thing that happens is that the Friar shows her the corpse of Romeo. Now she knows that she can no longer have a life with him. Not on this earth, anyway. There is a possibility that they may get together in the life to come, so she commits suicide. She wouldn't have been happy being Mrs. Paris anyway.