Progress?

Today I spent some money out of the gift envelope on gifts & a lamp for my sons room, and have felt guilty ever since.

The total was $7 at the op shop.
Not a big deal you may think, but hey!, I'm attempting to get ahead daily.
If this were everyday it would be a big problem.
I did spend yesterday too, o oh.

I had been wondering how this would play out in our ticght budget but (this month at least) there is a little wiggle room. I'm letting myself off the hook.
I want Maltesers and haven't yet had any, just think it will make me want more.

Anyway.

I am in a dilemma over $7 today and $34 yesterday, food & household items. OK I did buy some lollies in the food and scoffed them all in the car on the way home, but that doesn't change the total.
I had been doing so well with the envelopes, and i shall again but I just don't understand my downfall.
I like spending and it has been a cash drought for a while here &  I just got carried away.

I am getting too serious about a slip up but I would really like to hit some goals this year and can't let small amounts get frittered away daily, thus eroded any progress we may make. 

How does one stay on track, focused daily on a goal?