Heartsick

[Sarah]

Sick at heart; extremely depressed in spirits; very despondent.

[Sarah]

To feel dull, or an ache, heavy, tight or otherwise unwell in your heart. Occurs when someone you love is far away, or you've done something to hurt them and you don't know how you'll fix it, or when fate conspires to keep you apart, or in any less serious but just as pathetically painful situation.

[Sarah]

Heartsick is when you're all mopey and Mehh

[Sommer]

Very despondent, typically from grief or loss of love.

[Cami]

very sad or disappointed

[Justin Bieber]

Despondent, typically from grief or loss of love.