Personally I'd try a SERM re-start at your age. You may have plenty of good, natural test producing years left in you. But I'd suggest a new doc to help if this one won't. Thing is you never found the cause for your low T. It would drive me nuts not knowing.

To young for TRT? No, no one is to young as long as it's warranted. Problem is to many docs don't take the time to find the root cause and possible correct it. They just immediately implement TRT which is basically a long term band aid. Remember doc's are not really trained in hormones therapy in med school.

When it comes to your libido waning a bit, it's normal. Your body suddenly responds to what equates to a massive amount of test that it's not used to. It subsequently settles down. We can't walk around 24-7 with wood, unfortunately.

Split your HCG to 250iu's X 2 per week. Even HCG has a half life. Consistency is key.