I like the image as is. As a few others have stated it looks like it could have been meant to be exposed the way it was. Whether or not it was the plan or not is another story. Keep working on the focus, one of the toughest issues of self portraits for the experienced and novice alike. I am not that good at it myself, I would say do a search on here and you'll come up with some good tips and pointers. (focus on broom handle or friend, etc.)
The negative space... I am a fan of negative space. To me photography is not ALWAYS stand alone nor should it always be. Although it seemed a bit sarcastic KMH did point out that sometimes there is a use for negative space other then using as it is and leaving it empty. Cards, Calendars, Poetry, just a to name a few. It may not be the norm for self portraits per say, but you could write a few verses telling the world who you are and you'd have a nice place to put it in this image. (If you are also into poetry.)
I can honestly say that I take some of my photographs with that very idea in mind. It can be very frustrating finding the perfect photo to go along with a poem and finding it just does not layout well on the page when intertwined with your text.