Would an injection of testosterone help me?

Depends: Testosterone replacement for men can help with fatigue, energy, muscle mass, memory and focus as well as depression. It can come as gels, creams, injections and compounded pills/creams. The level of testosterone, your response to meds and your compliance will affect what is the right medication for you. Speak with your physician.

It depends: An injection of testosterone (t) might help if you were hypogonadal, in other words, had low t. But it's unlikely to do anything if your level is normal & you feel fine. The controversy is how to define abnormally low - perhaps you don't need to get an f before you get tutored. Perhaps getting even a b grade is bad enough to get tutoring for a straight a student who wants to become valedictorian.