Please trust your own instincts and the opinion of a father who loves you. You are, indeed, on some kind of edge. I don’t think you are making excuses. I don’t think you are lazy. (Even if you were lazy and making excuses, it wouldn’t matter. You could still be one angry guy who is afraid of his own feelings!)
So — Please. Go to another therapist!
Not all therapists are alike. Not every therapist is a good “fit” for everyone who walks in their door. Sometimes it takes seeing a few before you find the right one for you.
Do your part. If you find you are getting angry at the therapist, say so! The only thing a therapist has to work with is what you tell them and what you are willing to show. If you are as good at repressing your feelings as you say, it’s unfair to think a therapist will be able to read your mind.
As a way to get started, I suggest you take your letter and this response to the first session. That will give you both a jumpstart.
Thank you for writing. You are right to be worried about yourself. I share your concern and very much hope you will follow through and get the help you need.
I wish you well.