making life difficult

i'm being discriminated against in terms of my maternity leave. my manager is being very difficult and trying to bully me into only taking four weeks of leave. she knows i can't afford to take more leave then what i'm getting paid for and i get four weeks of sick pay. but i also get two weeks of vacation, which she is trying to tell me i cant use. she's trying to say i cant take two vacation weeks in a row. i've highlighted the passage on vacation time and maternity leave for her in the company handbook(which says "i'm" required to take it) and it's covered under the family and medical leave act, i think. she is making it very difficult to insure my leave and im already 36 weeks. it's very stressful :( i had my son with the same company and same manager and she didn't make it this difficult with his maternity leave. then again, i only took four weeks because i only had four paid weeks(three sick, one vacation.). in two years i've gained another week of sick and vacation pay. i just dont know what to do:(