He broke up with me for the second time

Hi,
I want to know your opinion on my situation. English is not my first language, so sorry for any mistakes.
So, I guess I will start with my story.
I know my ex for eight years now. We were going to high school together and in our last year we got together. He was my first boyfriend.
I don’t know, if our high school is the same as in USA/UK, we’ll I’m 20 years old and he’s 19.
So.. We got together on 13th of June.
We were great together, everyone thought that we are great couple, that they can feel the love. We never argued, like not a single time. I felt really confident around him, I love him and I trusted him.
We even talked about moving together after the end of our school and marrying in a future.
In May he broke up with me out of a blue. I was devastated. Like a really have not seen it coming. And he hadn’t say to me why he ended it. Later he said that he’s not ready for a serious relationship.
I applied no contact rule and worked on myself. And it worked. After a month and a half of our break up I went out with our mutual friends and he was there too. The next day he texted me. We started going out and stuffs like that.
About a month ago we talked about getting back together. We talked about what went wrong. And he said that he doesn’t know. That he felt weird, that it was a bad weather. And that he realised that he don’t want to be without me, that he really cares about me. And that he knows that this is going to last. He wanted me to meet his family for the second time as his girlfriend. We wanted to tell out friends. Things were going great, we started swimming together and it felt right. I truly believed him.
Then the finals came. It’s different here than in USA. We have four classes, for example I had Czech, English, biology and physics, and we have to learn almost everything from these subjects, than we choose a topic and we talk for 20 minutes in that topic.
It was really stressful and he really supported me when I went for the exemination. He called me right after that and was asking me stuffs about it.
3 days after was his turn and u went there when he ended and he was acting weird. He said to me like 4 sentences and then he talked with his friend.
The next day we went to cabin with our friends for four days. I was in a car with my friends and he was in his car with his friends. What I didn’t know was that he was taking his ex too.
I was kind of upset. He asked me what’s wronged and said to him that he was ignoring me for two days, then he’s in car with his ex and then he don’t even said hi to me. He said that he was sorry, that he was stressed because of the exemination that it’s going to be alright know. He even kissed me. Like reeeally kissed me.
Well.. We drank a little bit. And he went missing I was looking for him for about an hour. I was calling him and when he finally picked it up he said that he just went for a walk, that he’s not made up from a sugar, it was raining.
I started crying. He don’t even looked at me. Then I went to his tent and asked him what he feels to me. And he said that he really likes me, that he may even love me, but that he doesn’t feel the same as I. And I asked why he said the things he said, he said that he truly meaned it when he said it, like that he wants to be with me, live with me and like that. I asked him if he discovered during the time he was stressed about the exemination that he doesn’t want to be with me. And he said that it’s not like that. And then he was silent. Then my friend was looking for me and that we should figured it out in a cabin. I said to him just figure it out. And went away. And cried my eyes out. The next day he didn’t even look at me and I went home. It was a week yesterday. He has not contacted me in any way. I called him yesterday, if it’s end. And he said that yes. Just yes..

I don’t know what to do. Until last minute he acted like a boyfriend. Like around 8 p.m. we were kissing and at 12 p.m. he ended it.
I don’t understand why he came back when he was with me for a month. I don’t understand why he said that he wants to be with me, that he wants me to meet his family, that he wants to marry me in a future, that he wants to live with me. And after month he doesn’t want it.
Why when I asked him if he discovered that he doesn’t want to be with me, he said that it’s not like that..
I don’t understand so many things.

What am I supposed to do? Apply NC for the second time? Am I even try again? When he broke up with me for the second time?
Please help, ask me anything.
Please.