<human>: So I've been dating this girl nearly 2 years, we were totally in love. Talked about getting married and making plans for the future. Well, we were hanging out yesterday, we had just gone swimming and I was driving us back to her house. I parked outside of her house and got ready to go inside. She turned to me and told me we needed to break up and she needed to stop talking to me at all for a month. I was shocked, and upset. I managed to get her to lower it to a week of no communication, but even that sucks. 

This is the girl I thought I was going to marry, and we seemed totally fine and out of nowhere she drops this on me. She hasn't changed her pictures with me in them on social media or anything, but she might just not have thought to yet. I just want to be able to talk to her and find out what's bothering her so I can fix it!

Can you summarize the given text in a few sentences?
<bot>: girlfriend of 2 years breaks up with me and cuts of communication with no warning. I need advice as to what I should do, both in terms of having the best shot of fixing our relationship, and why she could feel like that.