It can be extremely dangerous to bet out of control. Take my word for it, do not learn this lesson through experience.
Here is the #1 Law of money management: Never Gamble With Money That You Cannot Afford To Lose.
Successful sports bettors all have at least this in common - they know how to properly manage their money. Superior handicapping/betting skills alone do not make one a winning player. To win, you must want to win bad enough so that you will be careful enough not to give your money back to the bookies.
This is a very important concept. Once you have won money from a bookie or sports book, that money is yours. Keep it that way. Subconsciously, the bettors that think of the money as not belonging to them tend to give it back immediately.
So start training yourself to think of the money as yours as soon as it has been won - because IT IS YOURS! Now you will not be so quick to give it back.
Also, do not gamble with needed funds no matter how "sure" the bet may seem at the time. The possibility of loss is always very real. And by loss I mean financially and emotionally. Gambling with money that is necessary for something else is a sure fire way to get yourself all emotional about it. And then who knows how desperate you will get.
Playing under escalated anxiety not only ruins all the fun and stresses you the hell out, but it also probably destroys your ability to make sound decisions and win your bets! That's right. Bets made under duress and usually bad bets. So play the game strategically so that is easy for you not to get emotional.