I don't think you want to be taking that many darvocet at a time, Kathy. For one thing, it's got acetominophen in it. For another, it's got propoxyphene, which is like codiene. Even if it's not taking care of the pain you're running a risk of liver failure if you take too much in one day.
Are you keeping your pain diary? If not, then you should be. Take that to your doctor and show him/her what your pain levels are each day. Then let your doctor decide what to do.
Healing hugs and lots of love,
Dan