They act like they are a loyal, trustworthy, and most reliable person. Often they are with you, laugh with you in times of happiness, but they change in the bad times of your life. They are not the same as they were in your happiness. Of course, none of us want to suffer in bad times, but personally, I think one should face the opposite situation in life, at least for the life lesson. Only then will you realize what you are. And the funny thing is you will get to see their real face, that was hidden.
I think that's the best part, and one thing you can understand is how good they were in their acting role. You must stand in front of the mirror someday in the evening and instead of crying you will laugh at yourself, and trust me it was the best laugh of your life when you laughed at someone. We sometimes ask ourselves, was I stupid? Or am I dreaming at night? And do we sometimes pinch ourselves to see if we are awake or asleep?
It's hard to accept the fact that they weren't yours and you were fooled by them, going through a flashback of all those moments. You hurt yourself and think that when you came back, there were thousands of ideas for getting rid of all these rubbish things when you were back-stabbed by some self-centered person you called a "friend." But that's the part of life that the moment you fall. You will find fewer hands to help you and at the same time to break your trust and get people to laugh at you who will stand the other side of you.
But it's not a matter of being depressed; there will always be some hands-on your side to help you get out of a bad situation. For example, some shoulders always help you stand up in risky situations and face the cruel people who hurt you the most in a bad situation and, most notably, to forget about them to get you started anew.
And someone said, some people can't always stop talking behind your back because they don't like you, because they feel jealous of you and don't dare to accept the truth. So let them go because that's where their natural place is, At your back. Don't waste your precious time worrying about those who talk behind your back. As I said above, they will never stop talking behind your back, so stop thinking about them. And it simply means that you are two steps ahead of them.