Only I know how I feel

It's very rare for me to actually open up to a person about anything. And even if I were to share how I feel no one but myself can know for sure how I feel. It could seem like something simple, or not a big deal but still, no one knows except for me. So for someone to tell me I can or can't do something or that I should, you're really in no position to tell me anything when you really have no idea.