My girlfriend only acknowledges i'm there when someone makes fun of me. She wont defend me she laughs. Help?

i have to say hi 6 times and nudge her three before she will even say hi. she says she loves me every night when she texts but that is about it. i tell her all the time that she is beautiful and sweet but she stops talking after the first question.she says she doesn't talk to me because she isn't good at pda. Talking isn't pda. HELP!