Without PCT, azoospermia/oligospermia usually remains for and average of 6-7 months post-cessation of anabolic steroid use.
There are case reports of returns to normal fertily following 12 to more months of infertility following steroid use with the help of GnRH management and such.
So yeah, you can go back to normal. I do not know about testicular volume.
Longterm use is difficult to assess. One report mention 4 year abuse and return to normal following treatment.