Need Help!

I don't know what's going on or if this is a problem with the site or my computer, but when i'm reading a manga and scroll down, the pages only show up 1/3 of the way down my screen and basically stay in that space as I scroll through the page. It's really hard to explain, but like I scroll down and I can read the manga, but only in the confines of that tiny 1/3 space at the top of my screen. It's like scrolling through a post on instagram, but a piece of paper is covering 2/3 of the screen. Idk if this is making any sense, but if anyone can help that be great!