Why am i suddenly feeling sad for no reason?

[HEAL THE WORLD]

I have been feeling extremely depressed the past few days.
I have no idea why i'm feeling this way.

Lately i have been thinking lots of things.
I realise that i really yearn for deep connections with people, but i can't find anybody whom i can trust. People let me down all the time, and i always trust the wrong people all the time.
For example, i have an online friend whom i added on facebook, we always messaged each other on facebook, but one day he suddenly deleted me from his facebook.
He always told me that i'm one of his trusted friends but his actions contradicted his words.
He deleted me from his facebook, i felt really shocked when i clicked on his profile and saw that "add as friend" button. I felt so hurt that he deleted me like that.
I regarded him as my close friend. :/


And it's not just him who disappointed me. I have another person whom i regard as my close friend, but she uses the things i confided in her to humiliate me during arguments.
I don't know anymore, i have already lose confidence in people. Even my family also constantly criticise me and puts me down all the time.
I want to find someone whom i can trust. but the only person i can trust is God, because humans are all sinners and they always do things that end up hurting me.
but at the same time, i'm feeling so lonely.


How do i stop feeling depressed? How do i stop feeling lonely?