You really need to find a free job club (ask at a library's reference desk) where you can rise with a tide of mutual support, as well as gain employment and retraining tips. In the meantime, think about presenting another view of the perceptions you mention. To wit:
Who's more reliable day to day -- the young or the mid-lifers? Who's less likely to make costly errors because of inexperienced judgment? Who's going to have a better attitude because they've survived downturns and are more appreciative? What other advantages does your age suggest?
Until you begin to think in self-boosting terms -- that is, "crack the code" of selling your characteristics as a competitive edge -- you will just be another 55-year-old man who employers assume isn't as good a buy as someone half your age.
As a mid-lifer, commit yourself to trying harder in this age of shifting realities than you had to as a beginner in boom times.
P.S. Regardless of your ideological persuasion, as an older worker, any health insurance reform that removes the cost burden from employers will work in your favor. Moreover, U.S. employers are getting stiffed because they aren't competing on a level playing field against foreign employers that don't have to pay expensive health insurance costs for employees. Watch the news; if results favor you, work the new benefit into your employment presentation.
(E-mail career questions for possible use in this column to Joyce Lain Kennedy at jlk@sunfeatures.com; use "Reader Question" for subject line. Or mail her at Box 368, Cardiff, CA 92007.)