Well, your testosterone is actually within normal at 400's. The average range is 233-1009 ng/dL for a man in his 30's. You'd need to be below 300 to be considered low testosterone. Do you get erections? I don't know what your TSH levels are but if outside of normal and high, that can indicate hypothyroidism which can impact hormones. It can make you weak, low energy, almost depressed feeling and yes, low sex drive. Is your thyroid such that you are being treated for hypothyroidism? Talk to your doctor about this. And it does not hurt to work on depression while doing that as this can also be related to that. do you have low mood? Do you get proper nutrition and rest?