Do I have to worry about my video card dying?

Hello! I have a curious question. I have had no problems until last night with my now 5 month custom built machine. It's an AMD FX-8120 CPU, 8 gigs of memory, XFX AMD 6870 (with a custom artic cooler twin turbo 2 instead of the stock cooling), TX650 power supply running win7 64 bit.

The other night, I think I had overclocked my GPU using the AMD vision control center. Under Performance > Graphics Overdrive the default settings was 900MHz (GPU clock settings) and 1050MHz (Memory clock settings). I had set them to the max 1000/1250 and it helped improve my games alot (Guild Wars 2 specifically).

However, last night I was playing Diablo 3 with a friend and I noticed two off color pixel with parallel lines in the upper portion of the screen. Thinking this was just a fluke, I alt tabbed out. The desktop looked normally. However, after like a delay of 3-5 seconds afterwords, the entire desktop looked like every line was offset from each other. The resulting display looked like the same image being offset in two different directions by every other line. During this brief time I was able to see the screen, I opened up MSI afterburner and it was saying my temps was around 58C.

I know, long story, but, I alt tabbed back into the game and the two lines was still there. I alt tabbed out once again and it was the same results. I excused myself from the game and shut the computer down. I'm scared if this is my card dying on me. But any advise/information would be highly appreciated . Thank you.

Edit: I'm not even sure what to call this. Artifacting? Display corruption? I dunno!