I know exactly how you feel. This is my second round, and last year I felt "led on" by a prospective advisor. She was told me "we really want you to come here" and, "it seems like a perfect fit," etc etc. I got my hopes up, and then she informed me that she was choosing between myself and another applicant. She even told me I was offered a 1 yr assistantship by the addmission committee, but she had to choose, and needed to know if I would definitely come if offered admission. Needless to say she chose the other student.
Well, here I am again. This time, I have the attention of another professor from a different school, who seems just as interested as the woman from last year (an MS program), as well as two professors on separate occasions (from a professional masters program) telling me that he "really thinks I'll get in" and the other saying he'd be "shocked if I didn't get in." I find myself trying my hardest to think the worst, so I wont feel the dissapointment again if the worst should happen.
I know this probably doesn't help you to hear about my let downs, but just know you are not alone! Being asked to come back by the professor before you even left the office is a great sign! I think there are more good experiences than bad after a professor expresses THAT strong of an interest in a student. Being a veteran of the application process helps as well, or so I've found. Also, the waiting is most likely just making you freak out even more than you normally would. I guess I'm just trying to say, do as I say not as I do. Try to immerse yourself in something else that's productive. Reading helps me. I'm also planning my wedding, so that makes the time pass. You'll find out before you know it. Also, I know a lot of admission committee meetings get canceled and rescheduled many times. Don't stress!!
There's my two cents