Getting Jumped, what would you do?

Within the past two years on two different occasions, I have gotten jumped by people I've never met before. On both occasions, after getting hit, I ran from away from them. Afterwards, I end up feeling like a coward for not standing up for myself. The first time, they were two, the second time, they were twelve. Also, the second time I was hit from behind off guard. I had initially seen a pack of guyz heading my way but ignored it. It's not that I didn't have the to stand up to these guyz, it's just that they are a bunch of ruthless kids who will not hesitate to kill for now reason. I always considered the possibility of them have a gun, that is why have I fled on both occasions. Is it really worth losing your life over something so meaningless??