So confused and hurt please help

sorry this is so long! please read! Okay so my boyfriend and I have been together for 2 years and we are both 19 years old. I would appreciate it if you left our age out of this because that is not a problem. we love each other We had a very serious relationship he gave me a promise ring we always said no matter how tough things get we're not breaking up, we were also best friends in our relationship so everything was perfect, never really had problems. We spent every single day together and things were perfect but then I have recently moved a couple hours away In mid-august but we still talked and saw eachother as much as we could. the day before Halloween his brother was leaving for the airforce and they are best friends so it was hard on him he called me crying and confused and I was there for him. ever since that day he was confused and not very happy anymore but he says it doesn't have to do with his brother leaving which I thought it did then he would have this nervous feeling in his stomach all the time and that made him even more unhappy. We hung out to see what was up but he still had that feeling (btw there is no other guy or girl so please avoid mentioning that) turns out he still had it and thought it had to do with us but then again our relationship is the most important thing in each others lives right now. So he decided to end it. I was completely heart broken and just hurt. he said he just needs time alone and can't be in a relationship and we were just about to move in together in December. so November passed he was very very distant didn't talk to me much didn't know if he wanted to be with me he still says to this day he doesn't know what's right or wrong..so beginning of December came and we thought it was time to hangout and see what happens so I ended up staying over a few weeks. at first he still had the nervous feeling in his stomach and was confused and not 100 percent sure what he wanted but then eventually he told me he wants to be with me and try again because he loves me too much to just throw it all away and we've gone through too much. so I was happy he seemed happy most times but still a little distant and not as cuddly or anything but we have talked about how we think he is depressed and I mentioned anxiety. but I'll get to that in a second. So I went home Christmas Eve and we were still together. he went to another state with his family to see his brother graduate and then went to Mexico and today he is actually coming back. But anyways once I left he was more upset I asked if it had to do with me leaving to go home he said it could be SOOO things were fine until a week ago maybe. he started going on and off one day he wants to be with me then the next day he is unsure if he does then he says "we're gonna be together forever I'm sorry I get upset I just need you to reassure me sometimes that we're gonna last forever" so I thought things were getting better but eventually a few days later (just a few days ago) he tells me he has that feeling in his stomach again and it's bad again. so we talked and he is just unhappy because of that feeling and he says he only has it when he thinks about me and him so he said he is not ready for a relationship and can't be in one right now he tried to be happy but isn't and the feeling is making him always second guess things like if he wants to be with me or not and all that so he said he needs to be happy again and I agree I was gonna talk to him about this when he hung out which would've been tomorrow but now I guess not. so basically ever since he had that feeling in his stomach he is unhappy and he had always told me he is unhappy with everything in life and he's confused about everything so I asked if that was true and he goes "I'm not happy with you anymore ok? I said it!" he never talks to me like that..I cried and cried because he always told me I'm a perfect girlfriend and I'm all he wants and if he could control his feelings he would be with me but I can't force a relationship on someone and I understand that. so that was pretty much the end of the conversation and that was last night he just said he can't be with me Nd he's not happy anymore. I know it's nothing personal I'm doing but back to anxiety I looked up many symptoms and they all lead to how he's acting. so I'm thinking the nervous feeling is like he's nervous about our relationship of course but I don't know why he would be nervous and he doesn't know either but I am just wondering what should I do? what do you Guys think the feeling is/means? he says he stilll loves me I know he's not gonna get another girlfriend. has anyone else gone through this or something similar? do I stop chasing after him? do I give up? Thank you for reading this I know it's long but I just wanted to be as specific as possible.

he sounds a lot like me haha, like sometimes i'd want to be with my boyfriend and then there's other times i don't. we broke up about 5 months ago, but recently we got back together and i'm delighted! but i have that feeling in my belly too..that nervous feeling.. my advice to you..LET HIM BE! he needs to think? as you said you's got back together and then broke up again? but then again..your going to get really hurt if he cant make his mind up..