Ha! Don't worry, man, you're completely fine. First of all marijuana typically remains in your system for about 30 days and generally it will only stay that long if you smoke frequently. If you only took one hit and it was over 30 days ago, I'd be willing to bet large sums of money that you'll pass that test with flying colors. I smoke marijuana pretty frequently and I've passed a drug test before having smoked about 10 days before and I still passed. No need to sweat it my man...