I have to wonder if your girlfriend is depressed. She moved in with you from far away. Does this mean she left her family and friendship circle behind? Now she is working at a dead-end job 50 hours a week. Meanwhile, you are supported by your GI grant, and you get to go to school everyday. You get to meet people, to hang out and pursue studies that interest you.
Your girlfriend doesn’t need your complaints about how she isn’t exciting. She needs your help to have a more exciting and rewarding life. I hope you can find a way to talk with her about how you can help her explore some career options that are more rewarding. If you did some part-time work to support the two of you, could she drop some of those hours? Are the two of you developing some friendships with other young couples? If not, do talk together about how you can find other couples who share your interests. Are you finding fun things to do on weekends to enrich your lives and to give her something to look forward to at the end of a long work week?
Wonderful people are hard to find. I hope you love her enough to put in the effort to support her emotionally and to work with her to create a happier lifestyle.
I wish you well.