Lethargic

Main Entry: le·thar·gic
Pronunciation: le-'thär-jik,
Function: adjective
1 : of, relating to, or characterized by lethargy : SLUGGISH
2 : INDIFFERENT, APATHETIC

Main Entry: leth·ar·gy
Pronunciation: 'le-th&r-jE
Function: noun
Etymology: Middle English litargie, from Medieval Latin litargia, from Late Latin lethargia, from Greek lEthargia, from lEthargos forgetful, lethargic, irregular from lEthE
1 : abnormal drowsiness
2 : the quality or state of being lazy, sluggish, or indifferent

Not to mention that I had a headache.