A lot of gangsters like my girlfriend, and one of them is threatening me.

well as the question goes. this gangster is now threatening me to be careful when out on the streets, which means i'll probably get jumped. on the other side i'm worried bout my girlfriend because she has to deal with this stuff, and i'm really worried about her safety. what do i do? my girlfriends in another town and i'm still in high-school, while that gangster's in university. he out of the country, however. but he has lackeys right here and he's able to tell them to do anything. what can i do to protect my girlfriend and myself?