Thanks for the response!
I am sorry that I forgot to mention (just for the record) if you press control + alt and back-space keys you can exit your GUI as well.
The reason I posted this was that I had a similar problem recently and I tried to get into terminal by Alt F1 / F2 etc, but I could not?! Then I used ctrl-alt-back_space and only then it worked!?
Glad the info was useful to you !