I agree with Dakota, If you are getting stressed just sitting down at the table after registration you are playing with too much money. Always stick to what you are comfortable losing. In a tournament there is a 70% chance you wont make the money, a 85% chance you wont make the final table, and 98.5% chance you wont win...
How did I come up with that? I don't remember where I saw it, but it is documented that the most consistent/profitable MTT Specialist on avg. will cash only 30% of the time. Make the final table 15% of the time, and win only 1.5% of the time.
With that said, don't ever bet the house with a 15% chance for a solid return. along with a 30% chance to break even.
hope that helps....