Financial planning vent

Kerri
So last night I went to a maternity info session and left upset and angry. I'm a teacher and there are 7 weeks from my due date until the end of the school year. I have enough sick time to cover those seven weeks plus a few days if needed. 
Part of my benefits package includes short term disability. Since I have enough time to cover my maternity leave, I thought I would not use that benefit, since it only grants 60% pay. 
I was told by the hr maternity specialist that I HAVE to use the benefit. That I use one week of my own time and then the benefit kicks in and I can't use my time. I was in shock and asked her several times to clarify. I am so frustrated and confused. I have the time saved up so why can't I use it?? I am going to be short thousands of dollars if this is the case for no foreseeable reason. 
My plan is to call the company that grants the benefits on Monday and ask them if I can use my own time before letting the benefit kick in. I am just at a loss. Anyone ever heard of something like this? Seems like my careful planning had gone down the tubes.