The Collaborative International Dictionary of English v.0.48:

Love-sick \Love"-sick`\, a.
   1. Languishing with love or amorous desire; as, a love-sick
      maid.
      [1913 Webster]

            To the dear mistress of my love-sick mind. --Dryden.
      [1913 Webster]

   2. Originating in, or expressive of, languishing love.
      [1913 Webster]

            Where nightingales their love-sick ditty sing.
                                                  --Dryden.
      [1913 Webster]

WordNet (r) 3.0 (2006):

lovesick
    adj 1: languishing because of love; "strong men behaving like
           lovesick boys"

Moby Thesaurus II by Grady Ward, 1.0:

23 Moby Thesaurus words for "lovesick":
   adoring, affectionate, conjugal, demonstrative, devoted, faithful,
   filial, fond, husbandly, languishing, lovelorn, lovesome, loving,
   maternal, melting, parental, paternal, romantic, sentimental, soft,
   tender, uxorious, wifely