I got the "grey screen of death", should I be worried?

I have a Macbook Pro with Retina Display (2.3GHz Core i7, 8GB RAM) which I bought in late July. I just got the "grey screen of death" which I've heard about but have never got in the 5 years of owning Macs. I have read about it but people seem to get it when turning their Macs on. When it happened to me I was streaming a very low quality video and my screen seemed to go a bit weird so I clicked to check out the problem and my Mac restarted, then displaying the grey screen. The Macbook seems to be fine since and acting as normal. Could this just be a random little bug or should I get it checked out? I've been a bit worried about the hardware since I purchased this model since if I put a light presure on the casing around the trackpad area I hear a creaking noise, which obviously isn't normal. I also suffer from the ghosting screen, but I've heard quite a few early Retina adopters have had the same issue.

Another question, if worse comes to worst and my Macbook has to be replaced, will the guys at Apple be able to move all of my files and applications over?

Thanks in advance