You don't need to tell anyone anything. Do what you're comfortable with. If you're afraid that you'll hurt yourself and want someone to be there to help you, tell them. If you're afraid of being labeled and put in a box, don't. If it will make your life easier and friendships stronger to tell a friend or two, then go for it. Only do what feels right for you. Only you can know that.
There is no certain time. It could take you one month, three months, a year, 6 years, or a lifetime to truly get over someone. You could possibly even always have feelings for the person. BUT you must remember WHY it didn't work out. Don't dwell on the past. Learn from why the relationship wrong in order to continue forward, and find the one it will work out with. Life is to short to dwell and be sad over one person .
To err is to human. We make mistakes. But living in the past and feeling guilty about the mistakes you made is not a solution. Learn from it and stay determined that you won't repeat them. Do not blame yourself or feel guilty. You made them in the past, you're in "present" moment now, moving towards the future. So get over it. You've come a long way and you've a long way to go. You don't need to carry such heavy feelings in your heart. You can't go back and correct it. But you can work on having a better future where you don't repeat those mistakes. Stay happy :)
A trigger is an action, word, sound etc. that can bring about feelings of anxiety, depression and other negative feeling in a person by "triggering" certain memories. If you ever come across a saying, story or action that makes you feel negative then this could possibly be a trigger for you that you need to be aware of and look out for.