Harry Potter and the Philosopher’s (later Sorceror’s) Stone was rejected by a dozen publishers, including biggies like Penguin and HarperCollins. Bloomsbury, a small London publisher, only took it on at the behest of the CEO’s eight-year old daughter, who begged her father to print the book. God bless you, sweetheart.
You're shopping your novel around. You get rejection after rejection.
Cheer up. Read about the famous writers who've been rejected.
Then send your novel query letter out again.