So, you put pen to paper, as they say, and the agent is telling you that the sellers gave you a big, fat, "NO!".
Was it a decent offer? I mean pretty reasonable?
Don't sweat it.
Let 'em sleep on it.
I've seen many a time that either the next day or so the sellers' agent gets in touch to try to re-visit the proposal. Don't get all excited here... they probably still aren't going to take your offer as written, but they at least are willing to talk a little. Maybe come closer to your terms.
So there's my advice. Sit tight. You might be surprised as to how it all comes together!