Forced on maternity leave??

I left work early on Thursday because I was having contractions. There were not consistent enough to be in labor so I was sent home. Husband stayed home with me Friday just to be sure I didn't go in labor alone (we work together) we go in this morning and I can't clock in. Then my manager said well you said you were having contractions so I had them put you on maternity leave. I'm like what??? How is that even possible? Legal? Or your decision to make? So here I am 36 weeks and can't go to work. With kids and bills. And it's unpaid! I'm livid!