How can I be excited for my job again?

At first I was very excited with my job. I worked hard and my work had great results. It has always been my dream job but for the past two years I feel like I have lost my excitement and no matter how hard I try I am not good at it. It is getting more difficult and I have a lot of stress. I need to find a way to be more happy with my job again. Have you ever been in this situation? What can I do?
P.S. I can’t take a break to relax…