I've had that too, though to a milder extent, that eerie feeling that my life will just end, and at my own hand, when I don't even have a concrete plan. Not pleasant...

Don't feel guilty for not enjoying caring for your children right now. You are not a bad mother. You are suffering from a very serious illness that causes you to lose interest in even the most important things. You're not alone, and despite what the depression may tell you, this is NOT the end. You are going to survive this and be even stronger for it.

I hope your T appt goes well, and that he is able to help you gain a bit of control over this monstrous depression. And, of course, do everything needed to keep yourself safe, even if it involves going to the ER. Hope things get better soon.