Why do we feel sick when we are disappointed in love?

Question

I'm mean biologically what happens? Why did this come about from evolution perspective?

Answer 1

It is all brain activity....What goes on above the neck affects what goes on below the neck. Hopes, expectations, desires cause uplift in chemical reactions. Disappointment, unmet desires and expections etc., reduces them and causes a low. Thus, emotional highs and lows that feel or seem to affect the whole body.