Thanks to everyone who replied.
I'm definitely not an expert on rooting. But when you root your phone you do 'flash your ROM'. Now what that means I don't know.
I contacted HTC about this problem, they collected my phone and they 'flashed my ROM' because there was a system failure. So now my phone is working much better than before.
So anyone who's experiencing this problem. Contact HTC. You have 2 years warrenty and if you have original receipt you have more.
So that's my advice to everyone reading this thread. Contact HTC. If anyone has any questions, don't hesitate to contact me.