MBP really slow, trackpad not responding, MS Word on my Mac suddenly stopped working - can't save a document or quit the program, options are grayed out

Hello,

I've been working on my dissertation and suddenly every option on my MS Word has greyed out. I can't save this document, copy it somewhere else or shut the application. I really don't want to risk force-quitting as I might lose quite a lot of changes I've made.

I am using RefWorks Write-n-cite tool, but ever before I've had it I had similar issues several times.

On the slightly different matter, my laptop is also extremely slowly (Mid 2011, Yosemite) and trackpad is sometimes not responding...

When I try to book an appointment with Genius bar in London they say that no reservations are available...