I know exactly how you feel. Sorry to burst your bubble, but I think it's just euphoria (the happy feeling that one get after talking to a huge crush), except you two had a history. So you're excited to see him but sad because of what could have been. I really know how that feels.
It's only been 6 weeks and it doesn't sound like you're hardly over him. It might be best to stay away from him (besides the normal chit-chat IF you bump into him), and try not to over-analyze what he said (if it hasn't already started).

Trust me, I have been guilty of it, and it almost always makes me feel a lot worse/disappointed at the next encounter. You get a high from seeing him, and then you get sad. It's just NOT a good feeling.
Unless, you can honestly say that you have no romantic feelings left for him and just want to be friends? (That's going to be hard to believe, though)