I've actually been sitting on a similar problem. I'm READY to query with my next novel, impatient even, but my dream agent isn't open to unsolicited queries right now. Her whole agency is closed to them, and they do this regularly, stop accepting them for a few months until they get caught up with workload then open up again. They've been closed to queries since February but there's still no sign of when they'll open up again, and the waiting is killing me. I'm basically just wasting time as we all know the query process takes months anyways. But everytime I think about sending off a query elsewhere to start, I just kinda go, crap, what IF I get an offer quickly, before the other agency opens back up and I get a chance to query? I won't even be able to nudge them. And so I hold off awhile longer. Sigh. It's driving me bonkers.