Daily Budget Formula Needed

This is quite possibly a very simple question that I've spent so long looking at, have over confused myself. As such someone looking at it with a fresh set of eyes would really help!

I update a budget sheet daily over the course of each month in which I have an total amount to stay within. Currently my daily budget is simply taken by dividing this total amount by the number of days in the month.

For example...if my total budget is £5,000 then my daily budget in January (31 days) is about £161.29.

However my ACTUAL spend each day will often be over or under this figure, so on the first day of the month I may spend £173.40 and on the second day I may spend £144.32 (completely random figures simply for demonstration).

What I want is a formula within my daily budget column that will either add or subtract this over or underspend from the previous day to the daily budget, staying within my total budget for the month.

So far my main problem has been creating a formula that does not affect other columns within the sheet such as the difference in spend from each day, and also provides me at the end of the month with figures that add up to my total amount.

I hope this is explained clearly enough.

Thanks!