Tren can be some wicked stuff for side effects. The long acting version can take awhile to taper out of your blood after you have stopped injecting. It can take weeks or longer to see relief if a problem comes up. If you aren't using the caber any longer, one option would be to reintroduce it and see what that does for you.
Another possible issue. You didnt mention anything about taking an AI, but I'm going to asume you are. There is a chance that your AI is too high. If you push your estrogen too low, you will lose your libido. Other signs of low estrogen would be dry, painful joints and feeling lethargic. Everyone is different, so I can't give you an exact dose that will work for you with 500mg test, but I would consider lowering it, if you are on the higher side. It may take about a week for you to notice a difference.