My advice would be to top up your creative tanks. This might mean a walk in the park with your dog, a lunch with friends, or visiting somewhere with a great view. Writing and marketing can be so tiring, but it's also a lot of fun. Taking small breaks to find inspiration can help you begin afresh when you are back in front of your manuscript.
My daughter inspired me to start writing. She was unwell for nine years and I needed a way to stay awake at night. I had been on writing courses and a part of a writing group, so decided to write a book to keep me company at night, while I listened to her breathing. My first book, Babe Driven, is full of the sunshine and laughter that I didn't have in my life at that time. Writing the book helped me begin a new career. My daughter is fine now and tells everyone she helped me find my dream job! I wrote the book and then hid it in a cupboard for five years until her health improved. Now it's a bestseller, which means that lots of other people are hopefully finding happiness from the story.