Can someone help me find a movie that I watched when I was younger but I cant remember the name?

The movie is where this man builds a time machine and the woman that
he wants to marry gets killed so he tries to go back in time multiple
times to prevent her death but it never works but then something went
wrong with the time machine and he went so far ahead into the future
that the world had ended and he was in the time where the world was
starting up again with new people. HELP!! IT'S KILLING ME!!