Sounds to me like like you have a boundaries problem. You don’t know how to establish boundaries around you. You don’t know who you can trust and who you shouldn’t trust. For some reason, you’ve decided just to spill your guts to whoever is around in hopes you’ll find someone who will like you or love you or treat you properly.
Realize, this is purely a response to your question, and I am making wild leaps here. If you are really concerned about this issue, you need professional help. See a therapist. Of course, if my diagnosis is correct, then you need to see a therapist, anyway.
If I’m right (and I’m not saying I am), then stuff happened with you as a child that made you unable to predict how people would behave. You may have been hurt in some way by people you thought were supposed to be trustworthy. This left you with no way of knowing who you should trust.
You opted to trust everyone. You could have gone the other way and refused to trust anyone.
You have to learn who you can trust; who you can confide in, and who not to. Your urge to blurt out everything is curious. Not sure where that comes from. I suspect that you feel a strong need to be known. That you are lonely and are seeking for people who might truly understand you. In fact you may be desperate for this, and thus the urge to tell people things in hopes you will find people who will understand you.
Actually, now that I think about this, this question is an example of what you are talking about. It is an incredibly vulnerable question. You throw yourself out there and anyone could answer and anyone could tell you anything, and if I am right (and I hope I am not), you can’t really tell who to believe, and so if I tell you a plausible story, you’ll believe me, and if someone else tells a plausible story that is completely different, you’ll believe which ever story you read most recently.
Further, if you get a sense of cognitive dissonance about these stories, you might even get angry about things and take it out on one or another of the people who answer you, whether or not they are being helpful. The thing is, you won’t really know what is helpful or not.
The thing to do is to learn how to trust yourself. You might practice by setting up criteria for people. Think about what are qualities you find trustworthy. These could be things you value in yourself. Then ask how you tell if someone has these qualities—again, look for signs in yourself. Then apply these to other people.
In trusting, you can tell people everything, but you must dole it out a bit at a time. It is a testing situation. You tell someone something a bit important, and see how they respond over time. If they do what you expect, tell them more. But be patient, and always expect someone to trade you information for information. If you tell them something, they should give you a similar confidence. If it is not equal, something is wrong.
All trustworthy relationship are equal. You can not have more or less power than your friend or especially your lover. If you do, you are liable to be taken advantage of. Your trust will be broken. It’s a long process and difficult to learn. Good luck.
But as I say, I hope this is all nonsense for you.