RecentQuitter : This is a good question.
I had this same experience.
I have been on trt 3 times.
1st time I started HCG before TRT. I felt not much at all when i started injecting TRT.
2rd time I started TRT alone. First week felt much better in terms of mood, appetite, outlook, vitality, energy, strength but no improvements in libido. It lasted 8 days then started feeling worse and had to lower dose.
I changed to test prop a few months later and was getting erections within 30 mins of injecting. For the first 3 injections. They were getting weaker every time. After the first 3 i felt nothing. Also after the first dose I felt VERY hungry within 1 hour. Probably due to insulin sensitivity improving.
3rd time. My pfs has got worse since the second time and felt not much.
I used to think this was all due to estrogens but then I did a lot of blood work on AIs and found that even when my e went down I felt no better.
So my current theory is this. When you first inject the T is released and your free T goes up but your shbg has not had time to change so suddenly you feel the T hitting your cells. Then as time goes on SHBG is decreased as it was in me now there must be a reason why SHBG is high in some of us in the first place, perhaps it is attempting to bind up some metabolite which is being produced in excess. So once we force the SHBG down whatever it was binding up becomes free and then acts strongly on our cells. This is my current theory.
FOr me DHT cream was similar. I took DHT cream felt improved mood and outlook and the next day I felt a lot worse. This was while on TRT so it was not simply T reducing T.
It is that or perhaps some T or DHT metabolite but I doubt that.
My saliva progesterone is way over range so perhaps that explain this. As SHBG decreases free progesterone or progesterone metabolites increase.
So I would question you, why is your SHBG high in the first place? For me my free T is low because of SHBG is it there trying to bind up something causing our problems?
Take a look at my saliva prog in the attached image. Saliva is only a measure of unbound hormones? Perhaps TRT further increased this problem?