The closer I get to my due date the more I get annoyed with the person at my job that will be taking…

The closer I get to my due date the more I get annoyed with the person at my job that will be taking care of my duties while I'm on leave. I can only hold her hand for so long and according to my manager I need to start playing dumb because she should know the job by now. I'm just so annoyed I have been training her pretty much since I found out I was pregnant and she is just not getting it!