I totally suck!!! Trying to learn why that happened I discovered something called time frames!!
The point is, when you see a 30min chart trending up, you should also check that the 1hour chart, and the 4hour chart are trending up as well in order to get into a high probability trade. The 4hour chart was clearly going down and I ignnored that. That means the bigger picture was not aligned to my shorter term analysis.
But that's the point, it is good to learn, and even better if you are just paper trading.
If you wanna learn about time frames check this out http://www.babypips.com/school/which_timeframe_should_i_trade.html