Unless you deleted the WTF forlder your macro should still be there, have you checked in WTF/Account/ACOUNTNAME/SavedVariables/MegaMacro.lua all your Global and class/spec macro should be here.
For the character ones check in WTF/Account/ACOUNTNAME/SERVER/CHARACTERNAME/SavedVariables/MegaMacro.lua
Hopefully you can find them there.

@RangerFrank fortunately you read and performed these actions as described so you can just restore them easily.

If anyone else runs into this, try my version with some fixes here: https://github.com/aurelion314/mega-macro

I added a config page that lets you use mega macro without a couple of its features, hopefully making it more stable.

If the tweaks work well then I'll create a proper pull request later, but it may still have some issues. Let me know if anyone tries it.