When I was on caffeine I was on a lot of it. Probably around 400-600mg a day combining my pre workout with my daily coffees. It is one of my favorite drugs and I loved taking it. This was the last 15 years of my life.
I became quite irritable over the past couple years with the inability for my mind to sit still which spiraled me into manic depression. I slowly weened myself off for a few months and finally quit altogether 8 weeks ago.
I've noticed I am much calmer, my mind is quieter, and my bipolar 2 is no where to be seen. Life definitely seems "duller" which sucks. But the lack of excitement everywhere feels much healthier.
Working out is definitely harder, as is being productive at work, but I'm slowly figuring out ways to combat that. If you haven't taken a break I highly recommend it. Even to just reduce you tolerance so you can feel just how powerful a drug this stuff is.