V. if I may, you sound a little obsessed. Are you prone to feeling like you aren't whole unless you get certain tasks done and absolutely perfect?
Being blunt, you've set deadlines before and missed them as the work was greater than you thought, this could still be the case and you don't seem to have accepted that.
There are things that do have absolute deadlines for that must be done, which is great. You are seemingly then focussing on the important but not urgent stuff which is great BUT if the machine is starved of fuel or isn't maintained, it will break or it's performance be severely impacted.
A question for you, if you slackened off slightly on the timelines for some of the important but not urgent stuff, would that give you some time to sharpen your axe?
A few hours in the grand scheme of things wouldn't matter that much to the stuff that needs doing. The time used wisely would repair and replenish and probably shortened the duration of activity for a given task because you are working at peak performance more often.
- Nobody has ever learnt anything important from happiness and success; problems make us grow - Consult your plan, not your feelings - If you haven't set goals, how can you expect to achieve anything?