Finances

i am a single mom, i work almost full time (my son has special needs so we have standing appts each week) my funds are budgeted pretty tightly.  i am aware of this, ye somehow i keep spending on random things i dont really need and each time it sets me back i have to deal with bounced check fees which i cant afford.  why does this keep hapening.  do i need someone to handle my finances for me and give me an allowance?