Can't move, move camera, or use buttons.

[IndyNicky]

Happens in old worlds and newly created worlds.
I can't move the camera or use any buttons, besides E (my interact button) and the only reason I can use that is because the little window that says E to open when exiting a drop ship pops up. After that I can't press anything. I can use my mouse to click and point, so the game isn't frozen or running slowly, but I can't move or use buttons. Does anyone have a similar problem and/or how to fix it?