Natural remedy to relax my cat?

HI,My cat is 12 years old.There is nothing physically wrong with her.She cries so much and keeps me up at night.I try my best to play with her at night especially to wear her out.Doesn’t work.I am not sleeping and not in good health right now.Is there anything that I can give her to relax her naturally?She is fresh water and food down at all times and her litter box is always cleaned out.Please any advice!
Thanks Lisa