The Collaborative International Dictionary of English v.0.48:
Heartsick \Heart"sick`\ (h[aum]rt"s[i^]k`), a. [AS. heortise['o]c.] Sick at heart; extremely depressed in spirits; very despondent. [1913 Webster]WordNet (r) 3.0 (2006):
heartsick adj 1: full of sorrow [syn: brokenhearted, heartbroken, heartsick] 2: without or almost without hope; "despondent about his failure"; "too heartsick to fight back" [syn: despondent, heartsick]