I've found that you can't put a lot of weight in these tests. For a truly accurate T measurement, your blood should be drawn first thing when you wake up, three times and hour for two hours (a total of six draws). The average should then be computed.
It's not uncommon for weight lifters to have lower T. Actually, it's not uncommon for participants in any demanding sport to have lower T values. If you're overtrained, or nearly to that point, your T will drop significantly.
I didn't see your age, but anything below 500 is "low." What's more important than your total T level, however, is your free T. While your value is still in the normal range, it may be low for your age. They need to come up with a more specific range, specific to age, because as it stands now, the range includes levels for old men too. So while you may have a normal result, as per the lab's normal range, it may be low relative to your age group.
My endocrinologist said the best T level indicator is the bioavailable T result. Also, your luteinizing hormone and prolactin levels are important too (at least for diagnostic data).
As far as exhibiting symptoms, there are lots of things that can make you melancholy, sleepy, low sex drive, etc. A good place to start is diet and nutrition. Make sure you're getting plenty of vitamin D, zinc, magnesium, selenium, and cholesterol/saturated fat. Get plenty of vegetables and fruit (low glycemic). Wild caught oytsers get your linguini rock solid in a hurry (full of zinc and cholesterol). You could also have developed sensitivity to something in your diet if you're eating a particular food too often. Food allergies can make you feel tired. Get plenty of sleep, and avoid sugar. I'm sure you're aware of sleep's importance, and you've probably heard sugar is bad for you. But it does take a toll on T values.
Hope that helps