All lines Become Pixelated and Red

For some reason whenever i draw a line, or use the line tool, it becomes completely pixelated and red. It sometimes shows the actual line when i’m not hovering over the image, but it mostly is always pixelated. I’m not sure if this is a problem with the download, or if i messed around and turned something on or off, but let me know if you know how to fix this.

What are the specs of your computer?

It’s a Surface Pro 4 with 64 bit os, and 8.00 gb of RAM.

And intel core i5-6300U CPU