The Intimidating World of Publishing

Self-publishing several previous children’s books, I had no idea how intimidating the “real” publishing world is. From the query, the literary agents, the publishing companies, and then onward to the dreaded “wait-and-see if they’re interested in my manuscript” months, it feels…brutal. I’m still in that last phase of hurry up and wait, but I’m curious how many others out there feel the same angst every time they submit a manuscript? What do you do to pass the time, besides research and writing?