Help! I have trust issues?

Maybe saying that you are too trusting is not the issue. Maybe you are not being honest with yourself. If you respond to people in a way that will benefit you, and not try to please others, you will have a better chance of seeing just how a person is before you get a chance to get screwed over by them. It sounds to me like you are a "people pleaser" and people pleasers never please anyone, not even themselves. Especially not themselves. Try putting yourself first and pleasing yourself. It's not selfish. It's the way you're supposed to be because you can't love or please anyone else until you learn how to love and please yourself. Then you'll see that being naive and gullible is not what you want to be. You want to be fair and trusting but not at the expense of you. If you don't feel the people's vibes when they are lying to you it is because you are too busy trying to please them and are in denial of the way they are treating you.