You just made a wonderful application, but you need a way to manage everything. Time for making an admin panel. Unfortunately it would require a lot of your time, the time you could be spending implementing features for your users where they send emails telling how amazing you are for adding this or that. So now you spend your time sitting in the corner, looking at the keyboard as you would like at rabid dog, and thinking about your life decisions.
You don't need to spend weeks to get admin panel. You can get one in hours, maybe even minutes (while you're waiting for your cup of tea/coffee).
How you ask?
EasyAdminBundle. Just a couple lines of configuration, and you can manage your users, messages, cookies, or whatever you want. Need to change how it looks? No problem, just a few lines to change. Need some custom actions to be executed? Don't worry, the bundle has your back.
Go to the KnpUniversity and learn how to make an amazing admin interfaces using EasyAdminBundle.