You have already made the first (and most important) steps. Those are trying to be aware and trying to remain phisically fit. Our minds are the weapons but the body is the instrument (even if only to use a tool.)
With all do respect I would recomend a local martial arts class. Don't get hung up on the particular style, they all have their good and bad points. The things that all of them will give you are: some cardiovascular workout; a feeling of where your body is in relation to your agressors; a basic set of moves to defend yourself with; a better awareness of your suroundings; and a less than lethal option. Hope this helps, If not, at least you got your moneys worth (0 for $0!)
I've joined the 300.