Stop those thoughts, control your mind

So, aftermath then.
I slept long and when I awoke felt quite groggy. Yesterday was a low point, more due to the fact that it had started off well. I'm confused as to why it descended so quickly and why it led me to me feeling as suicidal as I was. Today I feel better but still a bit tense, I suppose you could say. The trouble with having a suicidal mind is that once you've accepted it and have even started planning it, anything that disrupts those plans makes you almost annoyed. As if you're weak for not following through with your plans. It's like having a nagging friend in the corner of your mind all the time,
'You can't think about buying that shirt, you're going to kill yourself. What's the point of planning to buy that or anything else?'
Silly isn't it? My own mind conspiring against me like that. It makes you tired, weary. I have to tell myself, 'Not today eh? Let's leave it for now.'
My depression, (I wish this illness had a new name, depression doesn't fit it anymore, especially as it is used to describe a 'gloomy' mood or an off day. The two are all too often interchangeable) is an illness that doesn't really have a big start point, no big emotional experience or background that set it off. I remember reading years ago about how metal illnesses usually start off in one of two ways:
A big emotional event, death of a loved one, some traumatic event or childhood experience that sets it off. These are usually quick and short.
Slow and steady. nothing in particular sets it off and it sticks around.

Which is mine, slow and steady. 
I could point to various stressful moments over its course through my life but nothing that big. Of course the divorce made it worse but apart from that, there isn't any one thing that started it off. Which makes it harder to accept sometimes. I think, we as humans always look for some sort of reason for conditions and I'm not different.
I have some therapy on Friday. 
I think it's probably about time.