It’s more than a longing. It’s an ache so profound you feel it in your chest. 
Sometimes it happens with the change of season; the smell of summer lingering in the wind, freshly cut grass taking you back to your childhood. 
It’s missing someone so much it hurts. Miles may separate you, even different dimensions. The pangs in your heart could explode into a million pieces bursting with love.
It’s being homesick for a place you’ve never been; you feel it drawing you towards it, summoning the very depths of your soul. 
A past life? Maybe.
You must have been there before, otherwise, how do you know?
You just do. You feel the energy. 
It’s love lost and love found. Appreciation for the love that was and the love that’s yet to come. 
This is Saudade.