For what it's worth, I wouldn't mess with
methadone either. I've never taken it, but I wouldn't mess with it (and I've messed with a lot of stuff, unfortunately).
I used to have dreadful cramps when I was young, so you definitely have my sympathy on that! I remember when they first came out with
naprosyn, and it was a Godsend. They used to tell us to take Midol, which is just this side of useless when your cramps are bad.
Can you get a refill on your vicodin from your doctor? Honestly, any time you get into self-medicating you're playing with fire. Getting into fishing around for equivalents, which is stronger, what will happen to me, etc.--you really don't want to go there. Please call your doctor and get a refill on your prescription.
Good luck and please let us know how you do.
Take care,
Maisie