Thank you for sharing your experience.
> Plus being afraid of being by myself; or alive even
I absolutely love being alone. I mean, I like to learn, read, watch, play, etc. which I can do on my own. Its when I am the least anxious. A rule of thumb is the more people around me, the more anxious I become unless I'm one of the many (not in the center of attention; though my odd behaviour can cause that). This is regardless of being in a state of psychosis.
After those 3 mild psychosis I had a long one in end of 2012 related to stress but not (AFAIK) to drugs. This one lasted for a total of approx 2 months. FWIW, the fact that I had those mild psychosis before, helped me during this time.
Is that the ideal way to threat a psychosis? I don't think so. The best thing to do -even if drugs are involved- is seeking professional help. Something I failed to do, because I distrusted that around that time.
Also, I can highly recommend mindfulness to cope with anxiety (and other negative feelings such as lack of focus/concentration, being/becoming oversensitive, even insomnia). I recently followed a course on mindfulness for people with autism and can recommend.
> I don't think you can control the psychosis, no - but you can teach yourself to get familiar with what is happening to you and therefore know there's nothing to be afraid of.
You can only control it so much, but the despair of feeling not in control is painful. It is a matter of accepting that and knowing that over time it will go away. What you need to do is focus on that long term. IMO it is a test of patience. As I said before, I feel like mindfulness can aid here. If you lack the faith though, do admit yourself. Right away.
> But my question is still that of: what if I, for once - could not directly control myself and would end up damaging or even killing myself?
During my psychosis I pretty much had no ego left, and could easily criticise myself without feeling any resistance or pain to that whatsoever. That is an advantage, one I feel the scientific community could indeed explore. I wasn't afraid of damaging/killing myself directly (if I was, I'd have voluntarily committed myself to a ward) but I was afraid of damaging/killing myself indirectly, getting in a worse state (after a while I slowly felt I was getting out of it). So I pretty much locked myself in a dark room with one laptop (on a decent brightness) and WLAN and a couple of bottles of water which I sometimes refreshed. The only time I went out of my bed was to pee (I barely ate; not hungry). I felt like I had that part under control though I must admit: it would've been more safe if I admitted myself at that point. In the beginning I could not sleep, and when I slept I felt like a waking dream. I had permanent headache. Both of that slowly progressed to a better state. I can also, regrettably, say that my brain was damaged; I felt less intelligent afterwards. With the correct professional aid and guidance such can be recovered till some extend, akin to with seizures.