It sounds like he is unsure what the future holds because of his job situation and not being financial stable.What I think he meant by " He isn't sure about a serious relationship" is if he has to move some where else to get a job he doesn't want to keep you hanging on when he may be on the move. If you were to move in together he wouldn't want you to fit all of the bills and the rent and he wants to be able to do his part. He seems like a proud man that believes in taking care of his woman. If you truly want him back you can work this out and possibly have a long distance relationship but are your willing to do that and support him in his endeavors? This is what you have to ask yourself and if you don't feel you can do it then I suggest you let him go work where ever he can find it and when he is stable financial and as far as having a place to stay then talk about the relationship. He seems to really love you and want you in his life and is conflicted because he feels like he is holding you back. Show him that you are in it for the long haul and that you truly want to be with him and support him emotionally.
With the economy the way it is today he is not alone in his struggles there are many couples that are finding themselves living separate and apart to make ends meet. What he wants is to be able to take care of you and contribute to the relationship and right now he just can't do it. Talk to him and tell him that you miss and want him back. don't lose someone that is special to you just because he is struggling financial and doesn't know about the future and what it holds that will eventually change and get better and then maybe talk about a serious relationship. Tell him that the two of you can work things out together and when the time is right then you can talk about your relationship but you don't want to lose him. Be honest about your feelings and ask him to be honest about his, if he thinks he is going to lose you he will open up about the way he feels about you. I suggest getting back together and taking things slow until he is able to find work and find out where he is going to be working before making any crucial decisions about the relationship and breaking up.
He is right you are victims of circumstances that being the economy and he doesn't think the relationship would last being a long distance relationship but it could work if you both put forth the effect to make it work. I would give him at least a month or so to find a job and find out where he is going to be living, things are going to be up in the air until he finds a job and gets situated so you really won't know what your waiting time will be but as far as mental deadline give him a month. You never know what the future holds, he may be able to find a job near you and may change his mind but he just isn't willing to be in a relationship living far apart. Only you know how much you can take and how long you are willing to wait. He won't be able to talk about a relationship until he can find employment and a place to stay so just have a little more patience and wait to see if things change when he find stability.