Ok so I did something that might have worked out and I have to share it in case it helps someone else! So I just ended up connecting a second monitor because I saw someone suggested it. The initial one was connected with a VGA cable with a DVI adapter on the graphics card and the second one was connected with an HDMI cable. So having done that, the second TV (which was 1080p) displayed 1080p, but the initial one (also 1080p) didn't display like that. It was at 1024x680 and 1920x1080 didn't show at the Screen Resolution settings, it only showed up to 1700x... So I opened the AMD software by right clicking on the desktop and went to Custom Resolution for the initial monitor.and typed 1920 and 1080 at the respective boxes. That made the monitor display at 1080p and although I haven't yet tried starting the computer with just the initial monitor, I've tried disconnecting the second monitor while the computer was on and although there was that flickering of adjusting, the initial monitor displayed correctly in the end. So I think it's been fixed.
MODERATOR NOTE: I am glad to see you have resolved your issue. To help keep this post on topic and help other with a similar issue, I am locking this thread.