Try Kicad. It is free, gratis schematic and PCB editor. Unlimited sheets. I think you can set the page size to what you like. It has quite a large component library (what is a bit cumbersome to use) but it is easy to create your own symbols.
I use it for all my schematics and PCB's. Some people hate the user interface, but I had never problems with it. Tip is to learn the keyboard shortcuts. They are essential.