Mug Rug

Tried my hand at a mug rug and some more FMQ. Broke the needle doing it! I need to use a darning foot and a darning plate to FMQ on my machine. I'm still getting the hang of it. Does the stitch size matter at all? It seemed like the size of the stitch depended on how fast I moved the piece. A lot of strain on the fingers and wrists... don't know if I have the action down alright or if I just need to get a walking foot and a machine that will drop the feed dogs. Any advice would be much appreciated at this point. :)