I've moved on now from doing the "vegetarian thing" to calling myself a vegetarian. And being proud of it.
Admittedly, I have slipped up a couple of times; tried a bite of famous tuna salad here, accidentally taken a bite of baked potato with a bacon crumble there; but for all intents and purposes, I have been a vegetarian for a solid seven months.
Over the course of the last year (since ditching processed foods and eating mostly organics), the headaches I used to get frequently have completely dissipated. Overall, I feel better. Aside from the physical bonuses, though, there are the parts of vegetarianism that simply make me feel like a better person. No longer are my own habits directly causing animal pain or suffering. My food choices are healthy for my own body as well as the world around me: I am not directly contributing to environmental destruction due to factory farming.
I don't say any of this with an air of self-righteousness or a feeling that I'm "holier-than-thou;" instead, I say it to reaffirm all the reasons I've made this decision and continue to live this lifestyle. Because really, the only person I need to justify any of this to is myself.
A couple of months ago, I had every intention of going back to eating meat, or at least eating fish. But for now, I am sticking with this vegetarian thing. I'm going to give it a good year until I revisit the question. (Granted, I may take fish oil pills in the meantime to get more Omega 3 fatty acids, but... that's a step I feel that I can justify for the health of my brain.)
Not to mention, I just picked up a prereleased copy of "Some We Love, Some We Hate, Some We Eat: Why It's So Hard to Think Straight About Animals" (Herzog). Ten pages in and I'm feeling pretty confident about my meatless lifestyle.