Suspended problem

I am new to Anki, so bear with me please. I am using a large deck for Medical School, and I went to suspend cards in a category of that deck, but I somehow ended up switching my suspended with non-suspended cards. Basically I want to know if there is like an “undo” button like on word or something like that. I have lost what cards I have done and I can’t remember which ones I need to get back. Please help me. Thank you.

The undo action doesn’t seem to work for toggling suspension.
There are always backups, but maybe your problem can be resolved more easily?
You would have to know which cards you had selected when you toggled the suspension. If you don’t, maybe you can think of any distinct characteristic the cards you want to unsuspend (or suspend) have ? Anki’s card search is quite powerful and can help you to find those cards in that case. E.g., you can filter for cards reviewed a certain number of times or during a certain time frame.