12&13 nmol/L is a bit low.
But once you jump on that test (or any AAS) you'll most likely end up with even lower levels afterwards. And that means you'll be headed for TRT for life,
which again means you'll have trouble getting any kids.
Are you on any medication at the moment btw?
Also, before trying a cycle, I'd suggest doing a SERM or power PCT to see if that's enough to change things.
I know it sounds appealing to use T when you got low-ish T,
but that means you will get even lower T back after you quit.
You should see a specialist about this, not just a GP doc.