More about bipolar disorder

Two weeks ago the Psychiatrist phoned me and told me that he thinks that I may have bipolar disorder. I have major depression - I have known that for a long time. Ever since that call, I started thinking about this and doing some research.
One thing that I always found strange and inexplicable is that I work better the day after a night in which I couldn't sleep. Today is a good example. I woke at 2:00 this morning and didn't sleep again. I managed to write a large number of pages in my document I am working on, design a complex database schema and study a bunch of strange ideas. In truth, I should have been bone tired.
An hour ago I found these:

One of the most signature symptoms of mania (and to a lesser extent, hypomania) is what many have described as racing thoughts. These are usually instances in which the manic person is excessively distracted by objectively unimportant stimuli. This experience creates an absentmindedness where the manic individual's thoughts totally preoccupy him or her, making him or her unable to keep track of time, or be aware of anything besides the flow of thoughts. Racing thoughts also interfere with the ability to fall asleep. This rapid succession of thought that is difficult to follow is known as "flight of ideas".

...the primary trigger for (and the primary symptom of) acute mania is sleep deprivation.

I can also 'work', when I haul myself out of bed at 4:00 and immediately start working.
What frustrates me, is that I have not realised this. For a long time, I experienced these periods I called "Hyperfocus", during which I am able to build incredible stuff and write articles and am generally creative. I have used Ritalin and Concerta for a long time and tonight I found this clause:

Some medications may cause symptoms that mimic mania. Some medications may trigger a manic episode through hyperarousal of the limbic system and subsequent sleep deprivation. These may include: amphetamines and other stimulants (Provigil, Nuvigil, Adipex), caffeine (caffeine/taurine energy drinks)

This matches my experience almost exactly. Then there are times when it doesn't work. Specifically when I feel I am depressed, but also "focused", but I cannot do anything. (Called "Mixed affective episode"). I never understood how I can simultaneously feel horrible and at the same time "Racing thoughts" occur. The meds do not help at all then.