I think the swings in your rating can be attributed to your thought process. NM Dan Heisman has written a bunch of good articles for ChessCafe.com in a column of his called the Novice Nook. A few of these deal specifically on thought process (look for anything referring to Real Chess which is what Dan calls the proper thought process in chess). In a nutshell, on every move you should be looking at your opponents threats. A threat is something that your opponent will do to you if you could not make a move on your turn (which, of course, you can). Typically, it follows a hierarchy of forcing move that goes checks (most forcing), captures, and other threats (least forcing - could be occupation of a strong square or other thing not in the previous 2 categories). Once you are aware of your opp's threats, then you must decide if you need to defend against those threats. If not, then you look at your hierarchy of threats (checks, captures, other). You continue this process until you reach a stage of what Dan calls "quiescence" or one in which there are no strong threats in the position.

Developing a consistent thought process will reduce the variance in your rating swings.
 

Thanks for the comment. I'm also a great fan of mr. Heisman, and a regular reader of his column. My greatest problem is, however, that I don't have the time for long games, and in blitz, I don't have the time to implement that consistent thinking process. You don't learn to drive at 100mph. So, I know my disease, just that I can't take the remedy.