I just want to say, statistics are not on your side, even if you had had a gun. You said that you were a martial arts student, I mean person, experience in taekwondo, and yet because this individual was so large and was able to overcome you even with your skills, and chances are that if you had had a gun, then he would have been able to get than from you and possibly use it against you
What's that one rule of self protection: "If a perp is going to kill you with your own gun it will be by beating you to death with it because you would have already emptied it into said perp."