Hi all! First time poster here, and I do apologise for the wall of text! I'm 24/M and I've been a vegan for close to 2 years and recently begun to perceive that I'm having some cognitive difficulties. Something like the past 2-3 months, though today I felt a bit more... "foggy" than usual. I understand that a forum is not the place to go for proper medical advice, but I don't expect to keel over in the next 48 hours and decided that someone on the internet might have some leads I can follow to see if I can help myself, before I seek medical treatment. That said, it's not serious, and I'm not even certain it's not placebo. I'm not a known hypochondriac and have always had good health. 

My symptoms: 

Lately I feel like I'm having a bit more difficulty comprehending what people say to me, or written words, than I used to. I feel I'm usally rather quick-witted but as of late I'm often at a loss for words. Lately I find myself quite often having to check the spellings of words that I definitely know how to spell.  I've been very forgetful, especially of small details such as, "did I ask my wife about this yet?" or "I can't remember if I faxed those forms yesterday", or even "what the heck is the name of the supermarket I always go to???". Additionally,  I've been somewhat moody. - This is alarming to me because it's out of the norm.

Factors I've identified that may play a role:

I eat a pretty fair amount of soy. I do a soy latte or at least an iced coffee (decaf) most days, have soymilk in my breakfast cereal, and love tofu. I haven't had any allergic reactions to it, but I have relatives who have known food sensitivities. However I've been high-soy for close to 2 years.

I (mostly) cut caffeine out of my diet about 4 months ago. I was (and still am) a pretty heavy coffee drinker, but I only do decaf now. I'm aware that it isn't zero caffeine, but it's certainly a lot less than I used to consume. The first 2 months after quitting caffeine my sleeping patterns improved but otherwise I felt no different. 

I take a B12 suppliment daily, and a small multivitamin a couple times per week. I'm getting sufficient sleep.

I've had a moderate amount of stress in my life lately, but I've gone through periods of higher stress without any kind of cognitive issues. 

I eat a varied diet which, as far as I can tell, supplies me with sufficient vitamins / minerals / protein / fats / carbs. I'm at the lower end of a healthy weight for my size and it has remained stable since a few months after becoming a vegan.

I have been using a high-fluoride toothpaste to treat a pre-cavity so I hopefully won't need to get it filled. I don't buy into the conspiracy surrounding fluoride but I thought I'd throw it out there anyway.

Right now, that's all I can think of off the top of my head, but I may me forgetting something I intended to say (lol). Some educated suggestions, personal experiences or even just questions would be welcome.