why did my acrobat program stop working and it says my trial period is over?

what version?

if subscription:

check your account to verify your subscription is what you expect and to verify your adobe id (used in the next step), https://www.adobe.com/account.html

if your account shows

a. your subscription is active,

1.  sign out and then back in to your cc desktop application using the same adobe id above to verify your subscription:  http://helpx.adobe.com/creative-cloud/kb/sign-in-out-creative-cloud-desktop-app.html

2.  if that fails, https://helpx.adobe.com/creative-cloud/kb/cc-reverts-to-trial.html

if your account shows

b. you have no subscription and you're paying for one

1. using a browser that allows popups and cookies,  contact adobe support during pst business hours by clicking here and, when available, click 'still need help', http://helpx.adobe.com/x-productkb/global/service-ccm.html