leaving work

I got a new job when I was 5 months pregnant as a pharmacy tech. I have Spd and can barely walk or even lay down without excruciating pain, so I had to call out and informed my work that I'm now on bed rest for the remaining of my pregnancy. I'm currently 8 months now. I did not plan on coming back to this job after I've stayed home with the baby so do I have to apply for the leave of absence? Or can I just leave it as is? I only ask because my manager told me to pick up a leave of absence form? Is that just if I want to come back?