Glad you're hanging in there and doing what you need to do.

I don't know if this would work for older kids....mine are just 3 and 1. But when I'm in a dark place, it almost feels like their needs are amplified and I feel smothered. I've found that it helps if I say to them "I'm here for you for the next XX minutes...." 20, 30, or just 5 if that's all you can offer right now. And I make every effort to be totally engaged with them and focused on them for that short period of time. We play a game or read or go for a walk or cook something together. And then I either go back to being alone (mentally more than physically, since toddlers can't be left alone). Or sometimes I get caught up in what they're doing much longer and feel better as a result.

I don't think you will fail.