Congrats on the submission! What publisher did you submit to? Did you submit to an agent? If you get a rejection, just roll with it, they happen. Good luck! A lot of people are nervous when submitting.
The only advice I have, and this comes from a few professional authors, is to be prepared for the possibility of many rejections but don't let it get you down. Just keep writing and submitting. Eventually, someone will accept your work. The key is persistence.
Who did you submit to?