What does this mean?

So my boyfriend and I have been going out for seven months. Only, this past month has been weird between us. I feel like he doesn’t like me in the same way as before, and I’ve been confused about the way I feel towards him. I mean, over summer we didn’t see each other that much and I think that impacted our relationship. Anyways, we used to stay up and talk to each others for hours and hang out with each other whenever possible, but I haven’t gotten that impression for a while. Like, I feel like things are awkward between us for some reason. So, last night, I asked him if his feelings have changed and he said “I don’t know.” We have always been honest with one another and I was kind of expecting that sort of answer. So, my question is: what does “I don’t know” mean? I asked him if he wanted to talk about it and I never got a response… but yeah. I’m a little confused right now. I understand that the chances of us staying together forever was slim and all, I mean, c’mon, I’m just a senior in high school. But, yeah, thanks for taking the time to read this. Advice is great :)