"When one door closes another opens"

I try to grasp this- over and over again i repeat it to myself in hopes that one of those times i will actually come to believe it. I've been closing my own doors lately-some without knowing and others unwillingly have been "closed."
The ceasing has been hard for me. I have found myself sleeping in to ridiculous hours to escape what im escaping. I dont know why so many things have changed or closed. I'm not really sure the purpose it is serving other than making me absolutely miserable. People just leave-things, situations, places, leave.
I would rather it not happen
But when i look back at other times when people or things left it was all for the better- and eventually something better did arise. However for once in my life i was completely content with how things were transpiring and it's heart breaking knowing that things can be so impermanent. They are liable to leave at any given time- and me stuck here dealing with the the emotion that it inevitably gives.
I really wish that people thought before they did things. If you arent REALLY interested in someone, dont fuck with their head. If you dont plan on sticking around then DONT come around in the first place. Dont lead people one. Dont say things unlesss you TRULY mean them. It complicates situations and it hurts the person you are falsely convincing. It would be better if we were real with ourselves and aware that other people's emotions are involved.

think. please.