Call from a query?

Never read about this happening...does it happen often?

I submitted a query & first two chapters as per submission guidelines. Agent called me the same day to discuss the content. The phone call was mostly about the writing and how it could be tightened but that he liked the premise. He asked me if I would revise and I said definitely. He also suggested i show it to some more beta readers to get their opinion on what works and what doesn't.

This seems unusual; what does it mean?

I'm definitely happy about it, but my brain's so fuzzy from not sleeping that I can't really... comprehend what's going on?

Okay - sounds good then! I sent him a polite email thanking him for his time and advice. My editor friend and I are going to get cracking on the prose soon here.

Got another friendly and enthusiastic reply to the thank you email with some more advice. Things are looking up for my vamps

I finished the agent's revisions and submitted them (the story is now 15k words less than it was when I subbed it). The waiting game begins.
The novel has another 4 fulls out and 1 partial, too. I'm crossing my fingers!