great runs always end s bad

[NuGHuFFeR]

Sounds like you are just luck-boxing it with no sort of BRM(bank roll management). Only way you could get from $20 to $300 in 3 days. Doing thi you are always guaranteed to lose it all. If you think about it, even the best players go on bad runs, so this means that u are not guaranteed to win every hand(OBV). If you only have 1 or 2 buyins and you have 1 or 2 cooler hands, or even just made a bad play once or twice(even the best players can make mistakes as well, we are only human)..well then you would have no more money to keep playing.
Google Bank Roll Managemnt. Then practice BRM. Then start stacking your money and counting the Benjis.

edit: oh yah and variance.. you should probably look that up as well