I'm having de ja vu, remembering all the waiting around I did on various agents who'd requested my full manuscript over the years. The longest wait was 18 months (yikes!), and the shortest wait was two days (the agent I signed with!).
Waiting is just part of the business - whether you're waiting on an agent or publisher. Granted, waiting on a publisher is a waiting of a slightly-different sort. It seems like a faster process (of course, I've only just begun and could be totally naive about that), and it's pretty cool, having someone else (the agent) waiting alongside me, also feeling invested in this publisher's decision. And sure, with this particular wait, I'm one step closer to the publication process than I was with agents - but - just as when I was waiting on agents, it could go either way. Either a "yes" or a "no," which would put me right back to Square One again.
I think what we writers choose to do with our time during the wait is important. Sure, it's tempting to refresh our email boxes 100 times a day, or wring our hands and imagine all the possible "what if" scenarios, wondering why it's taking so long to hear something. But I've learned to fight that (as much as humanly possible) by channeling my energy into one thing: writing. Or editing, like I'm doing now.
I need to have Book 2 ready to go, so that's what I'm trying to do, to keep my anxious mind occupied. So far, I've made lots of progress. The waiting period can actually be extremely productive! ;-)