You're having trouble getting erections at age 19!
At age 19 you should be a WALKING ERECTION!
If your nipples are "way sensitive and tender" and you don't easily have hardons all day long and throughout the night, you need a complete Testosterone workup! Sensitive and tender nipples with no erections sounds to me like your Estradiol (E2) level is too high.
Were I you, I would stop all supplementation until you get your blood test results. Some supplements (e.g., DHEA) can cause increased E2.
There can be many causes for high E2 so there is really no point to speculate or for you to project any "diagnosis" upon yourself.
Telling any doctor that you have tender nipples and no erections should prompt him/her to draw blood right then and there. Here are the tests you need:
Total T
Free T
SHBG
LH
FSH
DHT
Prolactin
DHEA
TSH (High Sensitive)
Estradiol
Complete Iron panel.
Not to unnecessarily scare you but you should not delay checking this out. If your pituatary or hypothalamus is the cause, they can fuck up other things as well.
Please keep us informed of the results. Good luck!
:smile: