Was drinking maybe 6 to 8 cups coffee had overload at work started to feel burnout but could the coffee be really what's behind it?

Yes: Coffee stays in your system upto 12 hours interferring with your sleep and may cause jitteriness .Suggest not more than 2 cups early in the day and observe for any changes.

Both: Could be both, too much work, too much coffee! try to cut back both and relax, if you can afford it! best wishes.

Yes: More than 100mg of caffeine ( 12-16 oz coffee) can cause you not to get a relaxing sleep. Also stress at work and work overload can contribute.