all point to low cortisol. Both high and low cortisol could lead to libido issues. If your cortisol is high then other functions such as digestion and reproduction shut down to deal with "flight or fight". I'm guessing low cortisol leads to libido issues b/c if your HPA isn't signaling your body to make enough cortisol it also isn't telling your body to make testosterone either.
The thing that this trowing me off is the weight lifting. I have read that it is a great way to raise testosterone but I think too much weight lifting causes a rise in cortisol. If you look on bodybuilding.com there are lots of articles about how to lower your cortisol after a work out to prevent the catabolic effects of working out.
You could try supplementing with testosterone and see how you feel but if it is an adrenal issue and you don't fix that first, you won't ever really heal. In fact, if you heal your adrenals, then maybe everything else will fall into place.
I too would wring my hands and ask 'why'. I had friends who worked out way harder, longer and raced. So why did I hit the wall and they didn't. Looking back, I also was an anxious teenager and still a worry wart and control freak to this day. Plus looking back at family history, there were members including my own mom who had major stressors and they probably had adrenal issues as well (except back then it was the norm to call it anxiety and give them a pill and when that didn't work, change the medication or dosage). Some people were just born with a lower cortisol reserve than others.
Do you have any one else in your family who may have gone through this?
What is your cholesterol like?
Cortisol and testosterone have an inverse relationship with one another. After my first adrenal implosion, I started to feel better with testosterone and estrogen supplementation (I'm a girl). By then, I probably exhibited high cortisol but those two hormones dampened the side effects so I thought I was fine. I was doing great..until second adrenal implosion. Without fixing the underlying issue which was probably low cortisol to begin with...I probably had set myself up for failure...so please be careful in finding out the root cause.