My ex was my everything and then he left

It's my first time posting, and I really need someone to consult about this. It's long. 

My boyfriend of 2 years broke up with me out of the blue.

Background: He (28) has high functioning autism, and I (27)  have ADHD and suspect to also be on the spectrum ( but can't afford to diagnose officially now). We met in University and connected really quickly, we had a lot in common and we understood each other like no one before. It really felt like we found the right person for both of us, the one we're meant to be with. It was mostly good since then, we had some disagreements we worked on and always managed to find something we're both comfortable with, we never hide problems and was always honest. We helped each other grow and improve, we really want it to work. We could've talked for hours and loved just being together. He was always honest and affectionate, and tried to communicate even it's hard to him. He never spared an 'I love you', always tried to integrate me in his hobbies and made an effort so I will enjoy them. Things went well and we talked about moving together after graduation, and getting married and start a family sometime in the the future. Our love and care for each other was greater than I can describe, there's nothing we couldn't overcome together. 

We just celebrated our 2 years anniversary a month and a half ago and everything seemed normal. We prepared for the second semester,  and made plans to do stuff together and even planned a vacation in the summer. Then two weeks ago we met, he told me he doesn't love me romantically anymore and doesn't want to be in a relationship anymore, but he still hopes we can be friends. 

It came out of nowhere, I still don't understand what happened. How can everything be fine one day, and the next day he felt so different? No signs of a problem, he didn't say something was wrong, he kept showing love like always. 

I tried to talk to him and understand what happened but he didn't say much and couldn't describe his feelings. It feels as if he just gave up on us. Like being alone was easier now. 

Now we don't talk at all, and he's acting like nothing happened every time I see him on campus.

I feel that I lost everything, he was the closest person to me and the only one I could really talk to and be myself around, the love of my life. He was my everything. 

I can't understand why he backed off suddenly? I know he process emotions differently, but how can he act like everything is fine? He said he hopes to stay friends, but It feels like he doesn't care about me anymore...

does Autistic person really can just stop loving someone in a moment? Is it normal to just back off like that from a meaningful relationship? Is he masking or does he really don't care for me anymore? How can I tell if he still cares? 

Is there any hope he'll come back? Is there something I can do to convince him to try again?