“I do want to stick to the vegan lifestyle as a longer term goal but I wanted to try the meat to see how I do if I eat it as a one off”
Doing things as a “one off” experiment really won’t tell you much about how your body will react longer term. When people do a change in diet, it usually takes a week to maybe a month before they can really assess any changes. Whenever scientific experiments do a crossover design testing a couple different protocols (whether diet, supplement, drug, exercise or other), they include a “washout” period of at least two weeks, so as to better separate results.
Also, you seem to have only been trying to go vegan for a few months or so. If you are already wanting to do “one off” experiments with meat (something you seem to have tried many times in your life already), then some part of you clearly doesn’t want to go vegan.
Note, many vegans notice a mental sort of decline over time. This can happen for a variety of reasons (maybe not enough B12, protein, poor digestion, lack of certain vitamins/enzymes found in animal foods, anemia, hypoglycemia or something else). If you are already starting to notice that it is hard to organize your thoughts after this little time, this should give you serious pause. What’s more important in this lifetime that your ability to think? Lierre Keith in “The Vegetarian Myth” noted that many vegans she knew had mental issues when she was vegan herself, and also had issues with anxiety and depression, as well as memory issues. You might want to review her book to see the potential downsides of veganism, before you attempt to dedicate several decades of your life to what is a relatively new and novel way of eating for humans (the idea of veganism has only been around for 60 years or so).
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