Such a good thread and I've had to miss it for days...
Rupert, you are what I call a "flexitarian."
I consider myself one, also, although my meat intake is even lower.
Cajun, farmer's markets are great resources for buying humanely raised meat. Other good tips are if the meat is certified "organic" (not "natural," which means virutally nothing. Organic doesn't guarantee the animal was raised outdoors, but it does mean they had some access to fresh air and were not ever fed animal or animal by-products (which is how the whole mad-cow mess started). "Grass-fed" and "grass-finished" are also very good terms to see.
In your case, if you want to cut back on meat you may just have to compromise with your body and find the minimum amount of meat you need to stay healthy. I admit I'm lucky in that I can go without meat and not feel tired (though excessive sugar saps me). Even cutting back on meat is still a great thing for the environment and for limiting the proliferation of factory farms. I think one of the things people get stuck on with the vegetarian thing is thinking that it's an all-or-nothing proposition and it's not. Every little bit helps- it's not useless to just cut back, either, and that way people who need more animal protein won't go into anemia in their attempts to help the planet.
I have low blood pressure, too, and sometimes the world goes black for a few seconds if I stand up too quickly. And I have A positive.