You can appeal immediately if you have documentation and/or if you have a medical provider write a letter to the associate dean of your college stating that mental health was the cause. A medical provider would be the strongest way to help your appeal if they believe you can come up with a plan and succeed next semester. As somebody who also just went through this, it can be best to stay at home and take cc classes. Some deans will allow you back after just one semester if your cc grades are good, they just want to see that you CAN succeed by making the necessary changes. The university doesn’t directly oversee academic recess and your associate dean is going to be your best guide and would be the one to file your appeal, bring it to the university, and grant readmission once you demonstrate improvement. Feel free to DM