How do I fix an anchor when it keeps going out? Here's a pic

It is flushed after I tighten the nut but when I do pull up, it goes out. It's not like the hole is massively bigger than the anchor. I was barely able to push it in. I can't even pull it out without using a tool. I don't think the anchor would pull completely out but doesn't give me much confidence looking at it.

Also, every time the anchor got pulled out, the nut loosen itself.