<human>: So, half a year ago I hooked up with this [19/f], who ended up being my girlfriend. Everything was perfect, I'd give her the occasional "surprise" gifts (little stuff, like a rose when I knew she was having a bad time, etc.). We bonded really well, we discussed our family problems, it was just perfect. All of a sudden, she's being cold. Really cold. All she does is make fun of me, and when I reply with indifference and an equally bad (sort of) joke, she either goes into a raging stance and starts shouting, or she just leaves and doesnt reply for a while. She asked me to come over to her place and talk it out. We did, we discussed every single problem we had (including our sexlife which started being TERRIBLE because she had a yeast infection and couldnt relax so it would be painful for both of us). Fast forward 2 weeks, things havent changed. We talked against last night, and she was just as she was before. Not cold, super cute, all fine. I wake up this morning, and it started again. She ignored me for straight 4 hours (she's always on her phone, so I doubt she didnt notice). I know for a fact she didn't cheat, for she was sleeping over at her best friend (I secretly arranged for them to do so, I thought it would help her if she talked to someone else). I just dont know what to do anymore. I dont want to lose her for no reason whatsoever, and I'm not a quitter to just give up without even trying anything.. So, reddit.. Could you help me in any way?

Can you summarize the given text in a few sentences?
<bot>: Girlfriend being extremly cold all of a sudden, we talked about it, she seemed super fine and everything went back to normal for a few hours. Things got bad again, for no reason whatsoever. Need advice.