Should I break up with my girlfriend?

Hi all,

Sorry for the incoming wall of text.

It's been a while since I've been on here. A little over a year ago I was detailing things I girl I was interested in was doing around me and asking if people thought she liked me. We ended up together and this Sunday is our one year anniversary.

However, I'm feeling a bit fed up lately. It's not an exaggeration to say she's always busy. Frankly, I feel like she doesn't have enough time for me and I'm just some hobby to her on the backburner. To give this some context: in February I saw her once the whole month and we hung out for about 3 hours. In march I saw her once, we saw a two hour movie and that was it. In April Ive seen her once, and it was 45 minutes to go out and get coffee. I have literally only seen her 3 times in 3 months. Normally I'd be waiting a week or two between seeing her, but this is just unacceptable. I never considered myself clingy or needy, but I do love this girl and seeing her so infrequently upsets me very much. I always feel very sad when I send my weekly message asking if she's around and she says no.

Back in February or March or so, I talked to her about how I felt there was a lack of communication in our relationship and how I had been feeling a bit depressed lately. She understood and did put in some effort to respond to my messages faster (she would previously take 6-8 hours to respond to "what was the physics homework?" Or "how was your day?". And when she did respond, it would be a one or two word response. "How was your day?" "Meh." How was the SAT? "Meh." I feel like it's not hard to write more than one word and give me a response that actually let's me know how things are going). She started to respond a bit faster and with more words and info which I greatly appreciated.

For background, we are both in junior year in high school and college preparations are ramping up. She has AP work to do and is on the varsity softball team. She does a club via the school and club volleyball on Sundays. I understand that she likes to have lots of activities and be busy, but frankly that always makes me feel like the least important thing on her radar.

I have always put up with it, but my last straw recently snapped. Prom is coming up soon and I asked her if she'd want to come down to my vacation house with me for the day afterwards with a couple of our mutual friends, and she told me she had already made plans to go out with a friend of hers that she doesn't even really like (she frequently complains about her and how mean she is). I kind of expected that on prom weekend, you'd want to hang out with your date who also happens to be your boyfriend of a year, but I guess not, and this really hurt my feelings.

I think that, while I would drop anything to hang out with her of I knew she was around, she only hangs out with my if she doesn't have anything else to do. I know that she will be gone the whole month of July and then other miscellaneous weeks to visit colleges, so over summer break I will probably only see her 3 or 4 times.

So I guess what I'm really looking for is some advice on how to deal with this situation. Like I said, I do love her, and I want this relationship to work out, and it greatly pains me to be thinking about breaking up with her so seriously, but I can't deal with seeing her once a month. I think I should try to talk to her, but I don't think there's a way to talk about it without making the conversation a "me or your activities" thing. And as mentioned before, I've been feeling depressed lately (basically the only time I'm happy is when I'm with her or with my friends) and the longer I go without seeing her, the more depressed I feel; and frankly, I feel like I shouldn't be in a relationship where it is making me feel more depressed than usual.

If I were to break up with her, I would wait until after our anniversary and prom, which means I wouldn't do it until the end of May or beginning of June.

Thank you for any serious responses.