I don't know how to help with the stress spending, except I tell myself "don't". It mostly works, but I have to avoid shops when I feel like that. And be so disciplined it hurts!
I found it was quite cathartic to make an excel sheet of all the regular obligations - direct debits, standing orders etc etc - every single one including the o/draft interest and the bank account fee thing.
Once I could work out what was left each month, I split that into weekly portions. You could do smaller portions so you have a 'leftover' at the end of the month, but try to forget you do that. If you're anything like me, I'd still be spending, knowing I have the buffer, even though it's supposed to be clearing my overdraft (savings? I wish
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Get out the budget on a given day, then leave the bank card at home until the same time the following week. You have to be so brave and disciplined though, because once the cash is gone, TS! 
It really helps me to see the money disappearing. I'm a sucker for dishing out my debit card left right and centre and forgetting I've bought stuff.
Also, if there is anything left at the end of each week, you could treat yourself. Safe in the knowledge there's still a bit you haven't spent sitting in the bank. I always used to do it on a Monday morning, so I could spend the leftovers at the weekend. No leftovers, no night out. Or new shoes. Or chocolate.
Hope you get some more ideas from people. Just realised that none of what I've said is mindset. Sorry. Will think that through.