Thank you very much Bob for the detailed explanations, and the grammar lessons. You are really amazing, and I appreciate my luck in getting you to reply to my thread. I made it uploading most of it, I'm not entirely sure if I will upload the rest. You've been great help

Studying Tactics (Part 1) - Valda recommends MasterRussian.com - YouTube

Studying Tactics (Part 2) - YouTube

Studying Tactics (Part 3) - YouTube

Yes, the verb "чувствовать себя" requires instrumental in the examples as follows:

Я чувствую себя героем. - I feel like a hero.
Я чувствую себя космонавтом. - I feel like an astronaut.
Я чувствую себя больным. - I feel ill.
Я чувствую себя обиженным. - I feel hurt.
etc.

Literally, this expression is something like "I feel myself to be...". The verb "to be" (быть) requires the instrumental: "быть героем", "быть больным" etc. The same is true for "чувствовать себя".

BTW, it is a very typical mistake Russians often do when speaking English. They use "I feel myself" expression. For example, if you are unwell, we usually say: "Я плохо себя чувствую". Russian people tend to translate it literally into English: "I feel myself badly"
And just чувствовать, requires insturmental?