Post redirecting to another trashed post


I just noticed a popular post of mine is redirecting to another post which I saved as draft and subsequently trashed. I don't understand what is happening. The said popular post has been online and working fine until about 20min ago when I noticed that when you click in the url, it redirects to a previously trashed post and then says "that page cannot be found".

I don't understand what is happening and what I need to do but I need it fixed before it begins to hurt my page. Please help urgently.

Thank you.