It's okay man and totally natural to burn out. This is where you can reduce your training to say once or twice a week and cross train something else. There's gymnastics, break-dancing, any team sport, whatever. Double bonus if your cross train activity benefits your jiu jitsu somehow. Ask yourself too why you're burning out on jiu jitsu, or anything in your life for that matter that you want to keep in it, and go from there too. Maybe you've hit a stall in progress, maybe you haven't varied your curriculum, maybe you haven't gone up and rolled with new people/body types/energies. There are so many ways you can make jiu jitsu, or anything worthwhile that you burn out on, a fresh and new experience. Try rolling with different types of music. Work techniques you've never worked on. Find a wrestling/judo/sambo guy and roll with him/her.