Help – I think I deleted something important

I noticed my urls showing domain.com/wp/category/post and wanted to get rid of the wp/category as it was too long and unwieldy. I deleted the /wp and now have lost my theme and the page is just white with headings and the posts at the bottom. I can’t log back in to change anything back. I thought I knew what I was doing – I should have known better and left everything alone.

Can anyone help me please.