What should I do if I violated my misdemeanor probation a YEAR ago and just found out that the police were at my Mom's looking

Yes. Hiring a lawyer as soon as possible will certainly improve your chances of avoid jail.

Best to take action now by hiring a criminal defense attorney in your jurisdiction, now rather than later. The longer this goes on the greater that chance that you may have police contact (of any kind) which will at a minimum lead to arrest on existing probation violations / FTA / and even possible outstanding unknown warrants from original court. You may have more control, with representation, being proactive and handling this now rather than having to react and consequences (if police involved in future events).

I agree, you need to hire a criminal defense attorney immediately. You can use find a lawyer feature to locate one in your local area. Best regards.