The nature of no-limit means that you can lose in one hand what you might have expected to win in the entire session (or more). That's how it goes; if you can't handle this, then move to limit - this isn't a snidey remark; it's important to know you have the fortitude to take the inevitable lost stacks.
This is a very important point to be rehashed. At the Micro stakes level. It is so easy to nickel & dime your way to an $18 stack on a $10NL table. Before you know it you have AA and some guy calls off his whole stack to chase a dream with J6Sooted and hits. Bye-bye stack. Protect your stack. You don't need to get their's every hand. At these stakes they are more than willing to give you all their money, just wait to have a monster and take it. At $10NL and even $25NL in alot of places, If the board has paired 5's, someone has trips or a full house becase they called your 5X BB raise with "an Ace", if the board has 3 to a suit, someone has the flush because they had 35 sooted, and they call your 5XBB + 1 after limping, because "they're soooooted". At these stakes, play the board, play their hand and above all protect that stack.