Increasing your testosterone may or may not produce the affects you are looking to achieve (self-confidence, etc). What it can produce however, is what is commonly referred to as "steroid rage".
Body builders in order to more rapidly increase their body mass, inject synthetic testosterone (steroids), and this is very effective. The side-effects however, are liver damage, thickening of the muscles of the heart, surprisingly...Shrinking of testicles, and uncontrolable anger and rage.
There are non-medical solutions to your issues, such as courses you can take. I would go that route first.