a couple things. 550 total test is not low at all. that is a solid number and you should be greatful its that high since you juiced way too young.
second your low libido is not gonna be cured by using test anyway. libido issues are caused by many different things. you admit you already have some mental issues going on, there is a link there. I would learn to live a more balanced and stressfree life. stay away from all drugs, yes even prescription... stay away from alcohol.. eat more nourishing food.. exercise. get good sleep.. and learn to be successful in life ... the more you stress out over it the worse it will get.
I am a walking example of this. I used to be worse than you my friend.. stressed out, i was on a bunch of prescription drugs, let my health go to shit.. my libido was crap.. that didn't last long, one day I decided I had enough and threw everything away in my pantry and decided to change back to the way I was before. and I've done nothing but obsess over health since then, and today I have a higher libido than I've ever had.
^That right there is some great advice bro. Steve has some great recommendations for you, and you should follow that to a T.
