At al level of 300 have you had tests to find out why your so low it can be you cortisol levels are low and you thyroid and this can make you feel depressed. Go to
www.allthingsmale.com and read
TRT: A Recipe for Success in this are the tests you need and why. If you on SSRI meds now this will lower your T levels.
http://www.priory.com/psych/sexdys.htm
If they can't find any reasion for your low T levels you need to treat this or later in life you will have all kinds of problems with you health Heart and bone loss are 2 that go wrong.