<human>: Give me the gist of the text in a nutshell

Hey Reddit. So for the sake of clarity I'll call my girlfriend Mackenzie or Mac for short(not her real name). So me and this girl have been together for about four months, and lately it seems like she has just been constantly upset at me. Whether it be for a couple of stupid mistakes I made to things that are completely surprising to me, it ultimately is apparent to me that she is upset most of the time. 

For example just recently she got upset because she said it didn't seem like I wanted her around my family; this took me completely by surprise as I really enjoy having her around them. But it made her upset and we talked and after that it seemed like everything was okay.

Another example just recently is about a week ago, I asked her to come to my school's basketball game to meet my friends and watch the game with me. The day before the game rolls around and I started to feel extremely sick and didn't know if I was going to go, so we just agreed that she'd come over to my house for a bit. Then the day of the game/the day we were going to hangout comes along and she was extremely upset with me and kept saying things along the lines of me not wanting her to go. This also took my by surprise as I really did want her to go with me.

Now as a result of these two things and a few others, she has said things like "I can't have a boyfriend right now", "I cant' do this" and "I don't know about dating you". Whenever she says anything like this it really sucks the life out of me and makes me wonder what kinds of things shes really thinking, especially because soon thereafter she'' say something along the lines of "you're not going to lose me". 

Reddit I just really have no idea how to respond or what to do in these situations; this is the first "real" girlfriend I've had and i really enjoy this girl and like everything about her, and I especially don't want things to end between us. I'm really just looking for advice on how to handle these kinds of things, and any help is extremely appreciated.
<bot>: My girlfriend is upset often and often questions her being with me, how should I handle that and how should I respond to her in those types of situations?