Astrology should never replace your own judgement, your own perception, your own gut feelings.
Nor should it be used as a crutch .. an attempt to deal with the uncertainty that is life.
Astrology does not predict outer events accurately. What it DOES predict is your inner mood, and that does have some effect on how things go for you outwardly.
Nor does astrology predict another person's behavior. It indicates their inner needs only. And the more brain-dead we are, the more we will automatically respond to our inner needs .. but most of us have at least some degree of self-awareness, so the influence of the chart is only that: an influence.
We have the ultimate control over who we are.
You are trying to foretell the future because life frightens you and you hope that astrology will calm your fears. Part of your fear is because you are young ... it takes a lot of years of handling adult life before we start to feel competent, and our fear of life diminishes.
And part of it is life experience with failure: if you fall down enough times, you stop being so afraid of the unknown and of failure. You realize that you will, once again, pick yourself up, dust off your seat, and go on living.
As for judging people's character, again, it is not trusting your own perception and gut feelings. All of us are constantly putting out subtle, subliminal signals ... not consciously aware of it. And others are constantly reading those signals, on an unconscious level. When you become aware those signals, it is felt as a vague "gut-feeling" .. you have a sense of unease about the person, or you feel a tie with them on first meeting them.
We cannot listen to our gut feelings very well when we are tense or anxious .. it's like static interference.
Also, astrology is not a belief system. It is a tool. It has its uses, and (as you have discovered) it has its abuses.
You are looking for security, when in fact life cannot offer the security you are seeking.
It is not the astrology that is at fault, but rather your fear of learning how to cope with the essential uncertainty of life. We ALL must face that task, and astrology does not remove the need for facing it.
So one way to quit abusing astrology is to just drop it .. you make yourself drop it, just as a smoker makes themselves stop smoking. No one can do this for you. And you have to replace it with something .. replace it with a psychological journey, with or without the assistance of a counselor.
Another way is to actually learn what astrology IS .. to approach it with questioning, instead of thinking you already have the answers.
Soon enough, if you are open to learning, you see that astrology cannot do what you are trying to make it do. It has its uses .. but not as you are using it.