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.
becuase some people love people and have you know what and be like you have a small you know what i hate you so then they get a divorce or break up and 1 gets drunk and high the other gets athother one to love the high guy says i loved her.
Some risk factors for breast cancer are things you cannot change Such as getting older or inheriting certain gene types breast cancer is also caused by stress so I think it is (true)
