What do you do when you Panic Attack?

I dont always know when im having one because i experince so much anexity that sometimes it build up in a panic attack and dont notice until i catch myself breathing really fast and have skewed vision or crying to the point i cant breath but i guess all i do is take deep breaths and tell myself to calm down sometimes after i relaxed the sisuation maked me feel so depressed and tired a good nap helps me feel better