We all make the occasional bad decision, and usually there's no one to blame except yourself. You may have signed a contract you couldn't commit to, bought a faulty product or spend your bill money on something else.
Remember tomorrow is just a day away, the troubles of today will pass. Finding ways to rectify situations may not come instantly, but they will come. Think it through, think of the positive outcome you would like to achieve and work towards it.
For legal matters, maybe you need to consult someone, for bad purchases, check the refund policy, and spending bill money, well, learn from that experience and remember for next time.
Budgeting in general can be quite difficult, with so many unexpected expenses, unpredictability of future circumstances and changing job markets, I've found it near impossible to budget at times. But keep trying to.