"Exactly" half of Imac screen Fuzzy

Hey there!

I was on facebook the other day and clicked an Imbeded youtube video. At the exact time the video started playing half of my screen has gone fuzzy. On the fuzzy side white and black doesn't seem to be effected, but the majority of other colours go a shade of purple or green.

Like i said in the question it seems that exactly half of my screen is effected (Left Side).

It's such a pain as im a university student and i use this computer a lot for projects. Anybody got any ideas on what could be the matter?

Thanks a million.

Dylan🙂