This is the million dollar question - and to make it worse, you used both tren and deca.
It could be related to:
1) progesterone
2) prolactin
3) overly elevated IGF-1 levels
I'm not sure what to take to combat progesterone related other than the drug RU-XX (birth-control/abort drug - don't remember name). Winny competes for the progesterone receptor, but it's unsure if the amount we take is useful/enough. I believe some have stated bromocriptine will help.
For prolactin related, bromocriptine works.
If it's from overly elevated IGF-1 levels, nolva is suppose to remedy this (reduces IGF-1).