Hello Sunny,
I purcjased a ruler 18" x 2" marked, at Hobby Lobby in a nearby town. Would that size help you out? I'll be going there again April 2nd, Thurs, & could get one to send you if you'll tell me your price range you'd want to spend. If they're too much (? don't remember) I won't get one, but wanted to offer. It has a raised knob in center so you can hold that while cutting. I've found it really helpful. I have bone spurs on my spine (causes lots of pain, swelling & discomfort), so know your fibro is similar. None of it's fun, but don't give up. Folks on this board give out great info, I'm new to it, but been reading for several months. Welcome & if I can help, please let me know. PM me with your address so I can send it if possible. I'll also look to see what fabrics I have in case some are your colors.
God Bless, Sheila Elaine