Taking a step back

So my boyfriend and I were taking things pretty fast in our relationship. When we started dating this summer we hit it off so well and he invited me over every night. When he moved into his own place he gave me a key (we had been together a month). From then on we were pretty much living together. He never gave me any indication that he didn't want this though. I thought we were on the same page. Every time I did stay at my own place he'd text me about how much he missed me and either asked me to come over in the middle of the night or came to my house. We were spending all of our time together. All of the sudden we got into an argument over the weekend and he tells me he's not happy and he wants a break. We've always had good communication so this was really out of the blue for me. When we talked it out he told me that he doesn't really want to take a break but he doesn't want to live together yet. Which is fine but I wish he had just been honest with me about how he was feeling from the beginning. And we've spent every night but last night apart and I won't see him again till Sunday but just during the day. This is really hard for me. I don't know how to undo what we were before. And I know that this is a good thing if we want this to be a long term relationship but this just feels wrong. Has anyone been in this type of situation?