Cantbelieve, first of all - it is OK to have days where you want the world to stop, to swallow you up and make this all a messed up dream - we ALL do.
There is a difference between thinking positive and being in denial. I think positively, in that I get up every day, and then I start Bee's preparation for the day. This is a positive because, at that moment, she is still with us, we are at home, and we have to take the good where we can find it. Do I enjoy the hours of "extra" work every day that is unique to Bee and kids like her? Hell no! Do I accept it because it is what keeps her with us? Absolutely - I have no choice.
Thinking positively is what has a parent sitting with a blind child and "showing" them things, the same positive thought has a parent reading to a deaf child with the child's head on their chest, so they can feel the vibrations. Positive thinking parents buy shoes for children who are not supposed to be able to walk, and give their child opportunities unlimited by what they can or can't do.
I think positively in letting myself think that Bee is not a "typically developing 7 year old girl" but is a darn fine Bee. She picked up the nickname (we actually DO call her Bee at home) because of the bumblebee principle: aeronautical science and engineering have proven time and time again that the size of a bumblebee's wings in proportion to its massive body should make it totally unable to fly. The bumblebee, having never been told this, flies anyway. We let her guide us - once she begins to show the tiniest emergence of a skill, we grab it and follow her, supporting it along the way. She has learned to read, and she can almost count... pretty fine for a child who would "never interact with her environment".
But... next door, we have a little girl who is 6 months younger than Bee, but is so far beyond her developmentally that I am constantly reminded of the difference. Thankfully, she likes to play with Bee (the trampoline in our garden has really helped with the kids' social lives ) but no amount of positive thinking will make the ever-widening gap between Bee and her peers go away. I think positively (and appear positive) in public and when I am alone, usually in the shower or in the dark late at night, that is when I lose it. I will admit to occasionally having one glass of wine too many when there is a nurse here to care for Bee, eating a bit too much (or too little), and well... the eyesight issues I am having right now are directly stress related, so clearly I am hardly an authority on taking care of myself.
I can't imagine myself seeing her off to University, her daddy giving her away at her wedding, even her being able to leave the house unattended - we live in today with Bee because I can't imagine a future.
Denial is not healthy, but neither is denying yourself the right to grieve. You may be familiar with the "stages of grief", but when the thing or person you are grieving is still right on front of you, it takes on a decidedly surreal twist... I wrote something a couple of years ago that is how I see the emotional handling of our lives, because traveling through grief for us is entirely different... here it is, if you would like to read it
In the meantime, if you are not sleeping, please DO use a sleeping tablet, at least if your daytime fatigue is getting overwhelming. Don't rely on them every day, because you will find that there is no sleep without them, but there is no shame in needing to take care of yourself once in a while. This is still very new to you, and no one can predict the future. Right now, you are still reeling from the diagnosis and what it could mean for the future. You have a million questions and no answers.
I promise you, it WILL get better (or at least not sting all the time). I may be in Canada, but if you really need to talk, I can buy a long distance phone card and give you a ring.