How do you deal with this?

My girlfriend and i have been through trials, but none beats this one. We planned on being together for a long time, and I know everyone else does but I want to make this one work because shes no ordinary chick. Her mom just found out she was gay and now she doesn't want me around her daughter, doesn't want me in her life at all. My girlfriend and I still keep in contact but we're drifting away because her mom is always on her case about who's shes texting or etc. I miss her and love her from the bottom of my heart, I don't want to let her go but.. Ugh! What should I do? Should I let her go? But I don't want to.. Stay with her? I'm hurting from not talking to much because of her mom. Help me, please.. Any other advice would help.