family medical leave

of time under family medical. my employer said no problem it would be unpaid which i said was fine . well my girl had our baby a week later than her due date which pushed me past my anniversary date so my employer just opted to make me take vacation days instead. is that legal? my biggest concern is that because that left my vacation for the year at 5 days so i used a couple sick days which count against you as vacation days so i then got a poor review and lost a raise i had coming to me