Look around the base of your Bromeliad for "pups" (baby plants).
You probably did nothing wrong,
you indicate that you plant has already bloomed -
one of the truths of the life for most species of bromeliad,
is that once they bloom they begin to die.
They usually stay attractive for a while, but ...
once those gorgeous flowers
the "mother plant" will stop producing new growth.
And eventually, just what you have described will begin to happen.
But DON'T PANIC - The good news is that most types of bromeliad
send up offshoots ("pups")from the base.
There are usually several of them around the base of the original plant.
They can be separated from the mother plant once they have grown to be
about one-third the size of the original plant.