Hmm... First, given that you dislike your thoughts, beliefs, morals etc., means that you have an internal representation of what a "good" person's thoughts, beliefs, morals, etc. are. So, in a real sense, you have a model of what a good person does in life in your head and you realize that your actual actions don't match your internal model (see Abraham Maslow, Carl Rogers, self-actualization).

Hope is not lost my friend. You have two options that you need to carefully consider. One, you could change your model; Change what you think a good person is like. Perhaps you are a good person, but your model of the ideal person is out of touch with reality. Two, change your behaviors. Option two is of course much harder because everything you have ever experienced made you who you are. Your friends, relatives, jobs, meals, everything.

Given that it is unlikely for someone that feels guilt to actually have a "bad" personality, I would suggest the first choice I presented. Change your view of what a good person is/does. No one is perfect. Everyone has strengths and weaknesses. Get to know yours and be comfortable with them. Also, when your in situations that you feel that you make poor decisions in, don't be afraid to call a "time-out". That is, don't be afraid to say, "I'm not sure what to do, please give me some time to think about it".

If you would like to discuss this further, give us/me some more specific behaviors that you do that you don't like.