unpredictable nature

We walked along beside one another Next to the blue water We looked for seashells and sharks teeth on the beach Just you and me It started to get cold You gave me your jacket and I thought that that was sweet 'Cause I didn't even ask you and You always put me first Even when you were feeling worse I build you up to keep you from falling down But what do you do when I am not around Do you fall into the nothingness Like I do when I'm without you You and I we've gone along for quite some time And I was trying to shield your heart from loving mine 'Cause your nature's unpredictable And you feel blue even when I'm with you And you say That there's nothing I can do