What is the main conflict in Replay by Ken Grimwood?

In Replay, Jeff Winston repeatedly dies and wakes up earlier in his life, living out 25 years over and over. He struggles with the meaninglessness of this repetitive life without a future, sometimes taking respite in drugs and sex. Eventually he meets and falls in love with Pamela, a "replayer" like himself. Then they realize their replays are becoming shorter and shorter. Soon, they will die, and they search desperately for answers, only to cause more problems. Finally, Jeff finds himself replaying over and over the moment of his death, until he comes out the other side with a fresh, unknown future in front of him.