Re: Can you help me please?
I'm not a teacher! But here are some improvements you could make to your letter:
Change "With this letter I would like" for "I am writing to you to"
If this is supposed to be a formal letter then you can't use short forms or contractions like "I've". You have to use the full forms (I have).
We don't say "it was to do", we say "it has to do". Bewilderment and perplexed sound rare. I'd have used confusion and worried instead.
Change "I always had a keen interest" for "I always liked".
I don't know what you mean by "pursuing the tail".
Change "till" for "until" which is the same but you should use "until" when you write.
Use "a" in "as bleak point of my life" so that it stands "as a bleak point of my life" or just say "points" instead of the singular "point".
Change "After" for something else or for "After that".
"and I look forward to hearing from you".
I think you shouldn't write it like if you were an emotionally unstable person or a person with mental problems (like a crazy person who thinks too much as if he were a phylosophist).
Again, I'm not a teacher.