Hello! If you were logged into your Mozilla account, your add-ons should have synced automatically. If you know which ones you were using, reinstall them. Maybe the add-ons are installed but Firefox doesn't show them, so check under installed add-ons in about:addons.

I hope I helped!

Vexi

If you check your Windows desktop, do you have a folder named "Old Firefox Data"? That folder is created by the Refresh feature (Refresh Firefox - reset add-ons and settings). If it has very freshly updated files, perhaps a Refresh (sometimes called a tune-up) ran at the same time as your update??