need help?

I’m really pissed at my self for getting my girlfriend in trouble and she’s not allowed to talk to me but she’s still going to talk to me but the problem is that her mom doesn’t want her to date me just cause I’m 18 and already done with high school ans she’s keeping me a secret from her stepdad and dad and stepmom she told her mom that me and her aren’t dating but I don’t like that she’s keeping me secret cause we live over 300 miles apart and how am I ever supose to go see her if her mom doesn’t want us dating so I need some good advice on what to do me and my girlfriend really love each other and don’t want to lose each other so what should I tell my girlfriend to do I really need help cause not being able to leave her comments on a social site and text her and talk to her on yahoo makes me very depressed and sad it makes me wanna cry I have to tell my girlfriend how I’m feeling but I just don’t know what to tell her to tell her parents so that they would let her date me