accidentally deleted boot camp in windows.. what to do?

I had a mac mini computer and I turned it to windows.

I had an app called “boot camp” which It’s allowed me to switch from windows to mac every time.

after 2 weeks I had a virus in my windows and I had to restart my computer again, I forgot that it would delete all my apps (the boot camp). after I restart my computer I remembered the boot camp (the app that allows me to switch from windows to mac) and it was too late cuz I don’t have it anymore.

all of my data is there. how can I fix it?