Installed wp-cms and it has totally screwed up my site!!

I don’t know what to do. I installed the plugin wp-cms on the advice of a friend and it overwrote my blogs main page. I deactivated it and deleted it and now my Amazing Grace theme is all over the place. I have tried deleting the theme and reinstalling it and it is the same as before, still screwed up.

The URL is https://www.nomadicmother.com Anyone who knows Amazing Grace will know it is not supposed to look ANYTHING like it does right now!

I installed and activated a different theme and it looks fine, it is just the amazing grace theme that has been corrupted.

How the hell do I retrieve it and make it look like it is supposed to?

Thank you LOADS in advance