Answer:
Sends you unwanted, explicit pictures and demands you send some in return. Pressures you to send explicit videos. Steals or insists on being given your passwords. Constantly texts you and makes you feel like you can't be separated from your phone for fear that you will be punished.
Lack of physical activity and genetics.
That means they could've cheated or broke up and if they don't reply to you in a while just move on and say I want to break up with you because that's sketchy stuff
It really depends on the situation. In most cases it's because you've emotionally attached yourself to a person and/or opened up to them. It also depends on the reason for the breakup. If you feel as though the relationship shouldn't have ended and you're still in love and/or still happy with that person you may question why they didn't want you, putting faults on yourself and making you look at yourself differently which can cause symptoms of depression or anxiety. Etc.