This is usually a sign that we need to change things up and bring something new into our life. Maybe you used to be passionate about exercise, but that is not doing it for you anymore. This is an opportunity to learn a new hobby, such as drawing or painting. Or maybe you should read different books and learn a new skill. If you are the artistic person who is feeling burnt out on being creative, maybe you can take the opportunity to exercise more.
How you bring new things into your life is up to you. There are many ways to do it. It can be as simple as changing your morning routine, the music you listen to, the way you comb your hair, the books you read, the way you exercise, etc. If the absent of excitement and passion in your life runs deeper and you do feel sad, apathetic, numb, or depressed, then you should seek out help. First step is to rule out any medical problems by getting a check up from your doctor. If you are physically healthy, but still feel depressed, then you may want to consider therapy.
Feeling depressed is like feeling trapped with no way out. However, there is usually a way out that you have no considered yet. Losing your sense of excitement in life does not mean you cannot find it again. You must look in places you did not consider looking before.