You should take a break from her, you're just being frustrated by the situation and the fact that you can't have a conversation bout it is the worse, I dont know your GF but she seems a lil bit off like she's the one who lost the item and then in the end she's the one yelling at you that is important stuff, try to have a talk with her to figure something out, also ask yourself the good questions cause if you're gonna be more frustrated with her than anything that's not worth it to my opinion just make a choice