Pregnancy discrimination in the work place?

So I am a nurse. I work in a nursing home as a wound care nurse and nurse manager. With me being a nurse manager, I am required to be on call and work long hours (12-16 hr days) and being pulled away from my job as the wound care nurse to be a floor nurse. Well may 1 I was 30 weeks and my OB gave me a restriction to only work 8 hours a day. When I received the restriction it required for me to be pulled off the on call rotation (there was three of us on the rotation) which seemed to cause chaos (as I was the one usually having to work all the extra hours out of the three of us) well, may 17th my boss decided to do a PIP (performance improvement plan) on me. Basically saying I have 30 days to improve the issues listed in the plan, which the issues listed were being caused by me being pulled away from working on wound care to work the floor due to being short staff on the floor. This is beginning to feel like retaliation or backlash for being pulled off the on call rotation and the PIP being implemented after my restriction sounds a lot like pregnancy discrimination. What do y’all think??