Trust me the pregnancy card takeaways doesn't work, there was three of us all pregnant at the same time and it was he'll with eachother there. The one used it all the time and would leave early or not get things done and would use that excuse all the time bc she was like couple week farther along than us and it used to bug me so much. I would just leave it alone and when she acts like that just walk away and take a couple minutes to yourself. She could be going through per menopause and feeling down about all the things that come with that lovely New stage of life. Hang in there.
I think you should do it in a nice way outside of work but be prepared to go off.
I hate being fake. I want to tell her about herself now.