I am trying to keep from falling into depressed mode.

I am normaly upbeat happy go person, even with the ADD. I try to look on the bright side of every thing including my Add because i realize it can have advantages. Today however there is just too much! Things that NEED attention.
I just done my Taxes yesterday and it was the deadline, the yard is aweful, my neighbor found a snake by my front door from lack of mowing, my house needs cleaned, my bills need paid, my mother is upset because i am not calling enough, my grown kids need things from me, i need to scedule some doctor appts, and get some last minute things done for work.
The list goes on and on!!!
What do i do? I got so overwelmed today that i had a crying breakdown.
My Dad had surgery last week and out of 3 kids I am the only one there to help him and my mother... I was there for 3 days and my already crazy hectic scedule just got worse.
I try so hard to priortize, but then up just saying forget it, it's too much and i tomb up in front of my computer playing some online game that gets my mind off everything.
Sorry so long here, but I just need someone who can relate and maybe point me in the direction of some tips, help or advise.
Yes i am on meds, yes they do help some, but I am 40 and just realised i have ADD. And now trying to undo so many years of the same patterns is like untwisting tangled fishing line.
Thanks again