GF denied me sex

Been seeing girl since Halloween, everything has been going well, she lives about 45-50 minutes away in another city for grad school. She comes up every weekend though, shes from where I live. We were hanging 1-2 times every weekend till break when she was in town for a couple weeks straight, during which we would hang out 3 days a week and she would spend the night each night. Last night of break she asked if I still wanted to see her when school started up and I said ya, why wouldnt I, she then said well we can only see each other weekends and we dont talk alot over text so it will just fizzle out, to which I responded Id come down once a week during the week day, she agreed that would work. I then come down the following week and everything goes well till at night when we start having sex she like ignores me for about 5-10 min and I start wondering whats wrong to which she eventually says nothing and we have sex. She text me the next night saying sorry for how she acted, I then say your fine, glad I came down. Hang out on weekend and then everything went well. Then on Weds she says shes really busy and cant hang out so I dont come down. We hang out Friday and same thing occurs with sex scenario. Hang out Sunday night and samething occurs and I get mad this time but I tell her Im not mad just confused, then she says it could be several things like her new birth control, tired and the fact she didnt want me to come down this past week because it makes her feel overly commited. I then say fine I wont come down often during weekdays since were both busy with school and work but its important for us to see each other weekly which she agreed, she then would not have sex as I she wasnt in the mood and I actually reacted this time. In the morning we have sex and then she sends me a text later in the night saying sorry, shes glad im not mad for how she acted and she will be better on saturday when we hang out next. Anyways the girl has told me she has a pattern of being distant in relationships and Im her first actual bf since all the other ones she cuts off when they get to close. How should I go about this?

Edit:  Would also like to add we talk more over text since break, I told her I usually only use text for meet ups and then said "I thought that might be it."