Look, in poker each decision counts because the number of decisions you're allowed to make is mostly dependant on your cards, especially in lower stake poker. So you must minimize your mistakes. But we're all human, and mistakes do happen.
DEALING WITH MISTAKES:
Remember, poker is only profitable if you calculate your odds
, or take advantage of arising opporunities in your table. Make sure you have a goal in mind in each hand and divise a plan to reach your goal. You're only given a minute or so to create that plan, as each hand is different and each player is different, but construct a plan that yeilds you the most profit in a hand, without investing your whole stack unless justified otherwise by your hand. Think of each decision as an investment. As an investor it is strictly up to you to ensure that your emotions don't cloud your judgement and that your ends justify your means.