I had a quick dig around Dr. Michael Eades blog since he tends to cover a lot of science about how hormones interact and effect obesity and lipids. He does mention that hyperinsulemia can raise testosterone levels in women (not men) and in men it can raise estrogen levels. A low carb diet will reverse the trend by lowering insulin, but doesn't seem to have the opposite effect. In other words, in men, insulin levels effect estrogen levels, but not testosterone. Look at Dr. Mike's post on
protein sparing effect and scroll down to the comment from July 15, 2006 where Dr. Mike responds to a reader question on this issue.
That doesn't really seem to be your issue anyway. You might also be interested in his blog entry on
phthalates in plastics and how they act as an anti-testosterone.
You don't say whether your test level of 300 reflected a significant change from before you started eating LC, so it's hard to know if your change in diet had an effect.
It's not clear how much protein you are eating now. You said you were eating only 80g-100g per day when you were trying to get blood test results that said you were in ketosis. If you're still eating this amount of protein, that could absolutely affect your energy levels. I don't know enough about you to know if that level is sufficient for you, but it sounds low. That's about the amount of daily protein I aim for and I am a 50 year old, sedentary, 5'9" female. With a weight goal of 150 you may be a bit shorter than me, but the average 29 year old man is much more active with way more muscle.
If you're not getting enough protein and enough calories, yes, think you could experience significant fatigue.
I'm not sure if this answers your question, but maybe it gives you some more to explore.