The first day back to work after vacation is always draining.
Got through it though - when you know your time will be truly productive because there's no post-booze physical and emotional misery you can plan out how best to deal with the day and have it actually work.
Getting back to the regular household routine is good too...I was so sick of it before vacation I felt like breaking things but the away-time helped me get my perspective back.
And speaking of "back"....I got MY car back finally and it just makes everything so much nicer any time I have to drive. Didn't realize (or maybe didn't -let- myself realize) how suboptimal sharing the other car was.
And now to sleep. Big fan of good sleep.