well, im scorpio and have exactly the same problem...
i don't really believe in those zodiac things... whatever.
like you i get easily distracted, sleepy etc when i try to focus on something. another bad habit of mine is that i start to think about how useful the things are that i do... mostly i end up stopping to learn or whatever i was doing.

one time i forced myself to change and my grades improved at least in tests , but all of my teachers already had prejudices about me so my final grades were about the same as before... so there was no point in improving at all and i went back to my old habits. kinda sucks :|