Dear Basma,
first you want to establish whether there is a need for your sympathetic nerves to activate you: Are you and those you live with  in a safe place?
If yes, then [https://www.parsleyhealth.com/blog/how-to-stimulate-vagus-nerve-exercises/|these activities] will help your Social Engagement System. There are some switches too, like squinting with both eyes towards the tip of your nose. Washing your face with cold water also stimulates the ventral vagus.