My email folders are all empty. Important email

I looked for an email in one of my folders last night and the folder was empty. All my folders are now empty. In the All Mail folder, emails between 10/3/19 and 3/31/20 are missing. I just updated to Catalina 10.15.4. I looked in Trash and the mail I am looking for is not there. I use gmail with Apple mail. Same is true on my iPad and my iPhone. Thank you for your help.