Was He Serious About Me or Was I the Rebound Girl??

Me & my ex James are 17 & have been best friends for 2 yrs. I ran to him with any issue I had. He was even the 1st person I called when I was having a breakdown over my other ex. I finally wanted to move on & I started getting serious w this one guy. I loved James since I met him but he was with a girl who stressed him out & was terrible for him for a yr. James broke up w her a month before he told me that he's liked me since he met me & we had an amazing connection which was true. He was persistent for a wk before we made it official. I asked him why he didn't tell me how he felt before & he said he didn't have enough confidence. Everything was going perfect. He begged to meet my parents to show me he's serious & he's bought me all these gifts for Xmas. Yet he tried breaking up w me 3 times out of the 2 months we were together. He's also bipolar & he doesn't take medication. The 1st time he tried to break up he took it back immediately. The 2nd time, we didn't talk for 2 days until I confronted him to fix it & the 3rd time was 4 days ago that stemmed from a petty argument. He didn't talk to me for 3 days & I reached out to him trying to fix it 3 times before he decided to end it. His reasons were "I'm not ready to be in a relationship. We should slow it down." & that he only wanted our closeness back.. not a relationship. I haven't tried communicating with him since cuz I read about this No Contact Rule. I just wonder if I should try again or just completely let him go? :/