Why did we really break up?

We've known eachother for a few years and a started hanging out a lot a few months back. The chemistry was undeniable and of course we started dating. He was the one who initiated everything. Our first kiss, our first date, becoming exclusive, the "title" of our relationship. He was even very eager to put on Facebook that we were in a relationship with eachother. A few weeks ago he started acting a little different. Given he's job has been extremely stressful and his weird behavior coincides with work problems. He said he needed some space to think about things then a few days later everything was fine again. Then a couple weeks later he just decides to end it out of no where. He says it wasn't out of no where and that he had been pushing me away. But it was hard for me to see this because his weird behavior would always been after a bad day at work. When breaking up he said we weren't compatible, but then said we moved too fast too soon (but this happened from being compatible and having so much chemistry right?). I miss the hell out of him. Is it really over or does he just not know how to ask for space and work really is the problem not us?