Another book or is it too soon?

I have an idea for another book. It keeps running around in my mind at night preventing me from sleeping.
But is it too soon? Should I wait to hear back about the first book. Their comments could make a big difference to how I write this next one.
But it could be many months before I hear from them.
To write or not to write, that is the question. (sorry, Will).
Berengaria.