I have been thinking about this thread over the past few days and several times nearly started a new one to send how you were doing.
It's good to hear you have someone who can help you see the point in things at the moment, or at least keep you from doing, by your own admittance, something silly.
Once thoughts of that nature enter your head they are insidious and pervasive, popping up at many points in the day, and may well stay with you for a long time, reappearing after long breaks when things take a bleak turn.
It's important to resist them and have a rational rebuttal to them-know they are wrong-know you are wanted on this earth-know there is a worth to life.
Make sure you recognise the mindset that comes with them, and have a plan in place of dealing with it.
It's often as simple as when you have made a decision to do something maybe not so sensible, before you act on it, you HAVE to call someone to get a second opinion.
In your case Kev seems the person to call, so make sure you do. Often breaking the chain of thought, and talking things through with another human will make things seem a bit better and less lonely, and prevent any rash decisions.
Do not expect this to be a short process, but acknowledging and accepting that is half the battle.
Realise if strangers on an Internet forum want you to stick around, that life and it's many participants want your company, and that you are not alone, and there is worth in it all.
Times are tough now, they may be for a while, but you WILL get through it