Look, I don't want to make small of your nisyonos, firstly because it's just not a cool thing to do, and secondly "Al tadun es chavercha ad shetagiah li'mkomo"(don't judge your fellow until you've been in his shoes), and nobody really knows what's going on by someone else.
But I will tell you one thing: I hope to H-shem in heaven that you spend most of your day just praising H-shem for how amazing he was to you. You have no idea what it means to suffer from some of the things - that for some of us are a regular part of life.
For your nesayon, the main thing by far is tefillah. Not just asking a million times. That too. Rather, making each time you ask - like your asking to live another day. Like you want it so much, that your willing to give anything for it.
I was a big daydreamer myself. I actually had an IMPOSSIBLE time controlling my thoughts. The truth is, most of the difficulties went away when I got married. So I can really only give you advice from when I was a bochur.
It is in a way one of the most difficult things to control. Because you don't have to go anywhere or make any preparations to slip up. It's always with you, right in your head. At home, at work, in shul, in the yard, in the laundromat, in the coatroom, on the bima, off the bima, in the restroom, while your eating breakfast lunch or supper, at a wedding, in the shower..... You get my drift. It never leaves you, and you are always vulnerable. Furthermore, you can't always be on guard, because if you are then you already fell in, because your thinking about not thinking about it.
So what I'll tell you is this: That thoughts pop into your head IS NOT YOUR FAULT AT ALL AND YOUR NOT EXPECTED TO BE THOUGHT FREE!!! THAT’S REDICULOUS!! IF YOUR HUMAN THEN YOU HAVE THOUGHTS!!
OK, now that I got that out, I heard from the pele yoetz that anybody who desires that a bad thought should never enter his mind, “Eino ela taavoh” (Is nothing but desire itself). Why? Either because he wants to be on such a high level that he doesn’t have to deal with these things, or because he knows he will have to remove it, and that is unenjoyable, and can be very frustrating.
The practical advice I can offer you (if you feel you are being pulled into the desire to continue the thought at the moment, and find it difficult to pull your mind away from it), is to make times during the day, say between 2pm – 4pm, and during that time everyday – you be strong, and don’t allow yourself any leeway to slip. No intentionally daydreaming about these things, and if they pop in, then GENTLY let it out of your head. And gradually move the hours up with your success, until you got the whole day in there.
Sounds simple, IS simple, actually works. Good luck man,
KG