It happened out of nowhere, I tried to run a preview and it just wasn't working for some reason. Any ideas as to why?
Unfortunately, your question is akin to ringing a mechanic to ask why your car doesn't work.
You have provided no information at all with which anyone can even attempt a guess.
You should at least provide either screenshots off your events that dtermine when to goto the layout, or much simpler, provide a .capx.