Waiting for publishers to get back to you is extremely hard. Last month, I learned an important lesson. After waiting for about twelve weeks to hear from publishers, I sent a query to be updated on the status of my ms. The one publisher that requested an R&R practically sent me a rejection right away to my query. I don't know if I ticked them off or if it was really "lacking". I also have to mention that the editor that asked for the R&R wasn't the one that rejected me.
One publisher couldn't find the submission and asked me to submit it again. So I have waited three weeks now. The other explained that it was with an editor and if I hadn't heard back by the end of the month to contact them again. I can say emphatically that even though today is the last day of the month, it won't be happening! I learned my lesson. I will sit back and continue writing and waiting. I will not, will not, will not make the same mistake again. If I even mention that I am thinking about it, someone should come and kick me in the ass!