iPhone glass clicking - What needs fixing?

I noticed about 3 months ago that the glass on the right corner of my iphone 5c (about 6 months old) was making a clicking noise when pushed on lightly and the glass looked like it had almost popped out about 2mm from the case. It didn't effect the screen at all until about one month ago when horizontal lines started sizzling through the screen, as soon as i pushed on the corner of the glass that was popping out though it would stop and go back to normal. I managed to push the glass back in properly but now the screen has turned to very high contrast and very dark, you can see faint outlines of all the open apps behind one another and it is barely usable. Has anyone else had a problem like this? What will I need to replace? Just the glass screen or more?