This may sounds completely stupid and like weird.. please don;t take offence at all to it!
Wherever you study and do work... is it messy?
I find when my rooms a mess I can't concentrate at all.. and as soon as I tidy it my head is clear and I can work alot better.
Also, make a list of every assignment/piece of work you ahve to do and write the deadline next to it... then decide which order to complete work in and cross it off as you go.. I find that helps too.
I do Welsh Bacc too (however, for me it is compulsory) since it is compulsory I leave that until last and make sure all ym mainstream work is done first (although I am liek you and do work last minute)
However, if Welsh Bac was an option you chose I suggest you don't leave it until last
With the money... set a limit on money each day. Write a list of what you actually need.. and what are just wants. Then buy the necessities first and if there is any leftover money in the day.. try to save it if you can.. that way you may always have spare cash. Also, remember to keep track of your money.. write down everything you buy in a day and how much it was... that why you will know where every penny has gone and where most of it dissapears too.. that way you can work out how to cut back on what most money is going on.
Sorry I rambled and I hope this is of some help....