You can choose:
1. your death because life is meaningless as someone who subscribes to nihilism, therefore your death will have no meaning to the rest of the universe at large.
2. to find a meaning in your life that is bigger than yourself that is also feasible for you to personally achieve. I personally subscribe to the ideals that the American founding fathers prescribed to America: support the wider society in Life, Liberty and the pursuit of Happiness. This is just one example of an ideal to support that is quite feasible for individuals to achieve, it's not necessary for you to choose this.