I am trying to use clone but every time I make a stroke it undos it immediately. I have tried restarting my computer but it hasn't changed. Any suggestions?

Which OS and which version of krita are you using?
Which clone brush preset are you using?
Have you used a clone brush before with no problems or is this the first time you're using it?
Are you saying that it seems to work during a stroke but then the cloned stroke disappears after you release the mouse button (or lift the stylus from the tablet)?
Are you using it on a single paint layer or are you trying to clone from one layer to another?
Can you provide a link to a full screenshot that shows the Layers docker and the Brush Presets docker?