Girl fried obsesed with boyfriend?

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I have a friend in college. We were taking a course together and we both had alot of trouble in that class so all the time he use to come over to work on the homework together. He has a girlfriend who kept on calling him every half hour or so. She already knew about us struggling with our homework because he told her beforehand. For our first homework it was ok since she didnt know we were struggling this much but for the following weeks she kept on continuing with the calls. We were given homework weekly. Those calls weren't really important to begin with so my friend got frustrated and switched off his phone during the times he comes over to work on the homework. Since then she cameover to my apartment parking lot looked for his car and left notes. He was stunned when he saw that she came all the way to my apartment for something that can be discussed later. I am wondering if she has something wrong with her psychologically. We both met each other several times and from what I seen she doesn't seem like something wrong with her at all and she knows me well enough that I won't do anything to split them up. But I think she is kind of emotional because I overheard my friend pamper her over the phone a few times. Does she have something wrong with her psychologically??