Why do I lose focus so easily?

It happens to everyone everytime, but to me, it's way and far too frequent and much more serious than you think.

Whenever I do TT, CM, doing puzzles, or playing a game, I often will go distracted fully and just get off topic. When I play a game especially, I would start to think about something like dancing pigs eating rainbow unicorn styled chocolates (okay lol of course not exactly but pretty much similar to those).

I always tell myself: "Hey Dead Ass (yes I'm dead ass serious), get back onto the game and think about those stupid and pointless stuffs later." But I could not, and will never (and that's one major reason whenever I lose, or win by luck or on time in blitz) simply because I COULD NOT.

While I'm already aware that I might have ADHD (I still must check in with a psychologist or a doctor to confirm this) because this attentive disorder has gotten to the better of me in EVERYTHING, not just chess. I still would like some tips and advices on how to stay focused on chess, because coping with this attentiveness issue is almost impossible in other cases. 

Thanks in advance.

Focus takes practice.

You would be better off learning how to improve your focus than going down the ADHD path.

This is actually a growing believe in psychiatry as a reason for so called ADD and ADHD.

i sleep when i play :-) so might do a few blunders. It is all hand reaction

I think people underestimate how difficult it is to focus on one thing. I think the mind is prone to excessive wandering, and you should not be especially alarmed, though I am a little worried about how this is affecting you in everyday life. The only thing I would say is perfect practice makes perfect. However much or long you focused in your previous game, try to focus with 1% more attention. Rinse, repeat, and you'll get better at it.

Ehh, if you say so...