Sports days and fairness

My son's school sports day. Every parent knows that, what the spring and winter equinox were to our ancient ancestors, the navitity play and sports day are for us. Of course, it has that terrible sense for me of being the last I'll attend, in all probability. Strange to think of it...made even more so by the fact that he's still ignorant of the fact that I'm dying.
I love being a dad. Perhaps because it too such a long time and was fraught with difficulties, I did so appreciate my son when he came along. And we've built so a great relationship. The thought of the heartbreak he'll have to go through is still devastating for me. I feel guilty at leaving him alone no matter how much I tell myself that it's entirley outside my control. I worry about the emotional consequences for him, the financial implications for him and his mum, the whole thing..
Seven is still so very little to have this dumped on your plate.
Still, he got 2 medals - a 2nd and a 3rd - the sun shone and it was a beautiful day. Trying to take some consolation.
Chemo tomorrow so I'll let you all know what happens.