Alicia, once upon a time I had the problem that you had, but it was not due to the number of orders, but due to the things going on in my life, like college, internship (more like a day job), hobby time, and sport activities. All of that lead to a overworking stress, which is terrible.
I dealt with those problems by extending my delivery time, deleting the option for one-day delivery, and raising my prices a bit. It is possible to hurt your sales, but you would be able to manage your time better. It took me around 5 months to gain back Level 2 badge. Nothing to be worried about, just try to fix things as soon as possible, so it won’t lead to different and more serious problems.
I hope that this can help to you and to other sellers.