Re: Hormone imbalance
You probably already know skeletal muscle makes T, so weight training's good for this. I'm not sure about low/normal FSH+high LH, I would guess that says something about pituitary-hypothalamus interaction, but I don't know what. Maybe it's something to do with levitra. I believe high LH+low T is generally a sign of poor testicular T production. Unfortunately it seems like TRT only makes testicular T production worse (forever after), so I think TRT's generally a bad idea unless it's absolutely necessary.
ED at 20 sounds rough. Could it have something to do with a nerve dysfunction? Diabetes or other blood sugar issue? Do you have low penile sensitivity? Do you take any vitamins or supplements or anything?
Could you have some underlying nutritional issue maybe? An excess of some metal (or bad fats trans & omega-6 fats are worse than saturated fats) might explain the difficulty gaining weight. Or low zinc, iron, potassium, etc. (or too high). If I were spending the money on hormone tests, I'd probably want to get mineral & metal tests and other nutritional tests too. There may be a simpler, better solution like nutrition (or metal deficiency or poisoning--esp. copper, fluoride, bromide, mercury, lead, etc.).
Have you had thyroid hormones tested? The pituitary gland, thyroid, hypothalamus, and other glands are actually all controlling each other, so it's possible that higher levels of some other hormone(s) might explain your situation better than just low levels of T. Did you test estrogen? hCG? stress & inflammation hormones? vitamin D? There are some minor-ish pituitary disorders that cause hormone disturbance and can be treated just with drugs.
Basically, there's a lot I would try to consider before potentially just masking the underlying cause(s) now with TRT.