Note to self:
I don't want to draw too wild conclusions about this yet, but I accidentally skipped two days of taking Omega-3 supplements and I had extreme difficulties to concentrate and a really distracted mind at work. The incident might very well have been just an accident, but the difference in feeling was pretty concrete and significant.
I'm pretty sure I'm not a "real ADHD" insofar as concentration problems haven't been ruining my life or anything. I do feel that my relative inability to focus (at times) has had a negative impact on various aspect of my life, but it's not like I cannot function most of the time or anything. But anyhow, the feeling at work, which I did recognize as a familiar feeling from my past (I've had a leave of absence from work for over a year just recently), was pretty much what I imagine real ADHDs feel.
It's not like I would constantly feel an urge to check if I have new email or if there's anything new on the web. It's more like the whole mind is completely distracted and it feels almost impossible to focus on anything. It's like a buzz inside the head. The idea of starting something feels almost painful. (Luckily there's always something one can do even if some big task seems, at the time, impossible to get started with.)
The strange thing is that this feeling occurred just after couple of days of missing my Omega-3 supplements. After starting taking those supplements, I recall feeling pretty "normal" most of the time I'm working. But like I said, I'm not sure what the real reason was. Sometimes I get distracted by the nature of the work I have to do during the day. For example, a lot of different tasks concurrently usually distracts the mind.
Now, I do track my mood during the workday, but so far I haven't looked at the data. It will take a whole lot more than just couple of days, because my work days are so different that it takes time to eliminate the effect of different types of work days from these measurements.