It's all too much - losing motivation as a leader

Hi all,

I've been managing, nay, leading teams for about 8 years now. I've moved up in my company which started at about 20 and now is close to 80. I am basically in charge of almost all facets of the company internally now but still report to a group COO and work alongside a couple of peers. 

My issue is that at the moment it all seems just too much. Every problem is mine and although I hear a lot from others about what needs to be done to help manage it I feel that ultimately I have hit a wall and breaking point and I am no longer motivated enough to try to resolve the problems. 

I worry because we have built a strong business with decent process and now my lack of motivation risks effecting the staff around me through my clear lack of enthusiasm to rise above and move us forward. 

I wanted to know if anyone out there has gone through the same and what if any steps did you take next?