Sorry but yes that is one of the purposes of the reset it removes extensions, because they could be the source of problems.

• An article about reset, with a warning Refresh Firefox - reset add-ons and settings

1. It would have been good had you bookmarked all the home sites of the extensions; assuming Firefox was working prior to the reset.But horses bolting !
2. No doubt you remember the extension name or function so search the addons site,and click to install when you find them
   • Use https://addons.mozilla.org/firefox/
3. As a last resort you could, temporarily reinstall the old profile as an additional profile but that is best avoided.

When you reset Firefox then a new profile is created and some personal data (bookmarks, history, cookies, passwords, form data) is automatically imported and the current profile folder will be moved to the desktop (Old Firefox Data). You will lose extensions and other customizations (toolbars, prefs) that you've made.

It is possible to recover more data from the old profile, but be cautious not to copy corrupted files to avoid carrying over the problem.

• https://support.mozilla.org/kb/Recovering+important+data+from+an+old+profile