bottom scroll bar keeps showing up on my blogger site

My bottom scroll bar always shows up when I'm on my blogger website, it's annoying me, because it gets in the way and it dosen't show up with other people only me, but when I click to zoom out (which is too small) it goes away, I'm not zoomed it, so it shouldn't be there, and the page isn't big enough for the bottom scroll bar to be there, I don't know why it's there! it may be my computer or firefox, it wasn't there before, but now its there, and I don't know why :(