Join the club - I feel exactl the same. Here's what I've been doing.
SHopping - I take out say, £200 food shopping money in cash for the month and seperate it into £50 each week. I do try and not go over this, but it does make me think twice before I do.
Personal money - I give myself £100 a month. £10 a week for 'purse' money e.g. a magazine, a drink etc and the £60 for treats. If I save my 'purse' money, it can go towards my treats (as an incentive). I put the money in a little pot and take out £10 a week, so I have money left at the end of the month.
Budget - I keep a little notepad in my bag and every time I spend, I write down what I spend it on. Again, it makes me think twice before I spend and I can see where my money has gone.
Little spends - I limit my trips to the shopping centre to once a month, because I have to pay to park there. I also ensure that I eat before I go out, so I don't spend money on snacks. DS is under two, so hasn't reached that 'I want' stage yet, but I will try and limit buying for him when out.
Lunch - I bring in lunch to work where possible, by eating yesterdays leftovers.
Saving my £2 coins - we have about £400 and its going towards our holiday next year.
Get a hobby - I've started to find things to do with what little free time I have to keep me from going to the shops and spending.
Its not the big things that cost, its the little things that add up. I guarantee you if you start to write down every time you spend and add it up at the end of the month, you will kick yourself when you see you've spent £20 a month on parking or that you've spend £30 and have nothing to show for it.
Don't get me wrong, I'm not great with money either, but I am trying and it is slowly working.