Help ladies? I've been with the company I work for, since 28th of September 2015. I made them aware…

Help ladies? I've been with the company I work for, since 28th of September 2015. I made them aware of my pregnancy as soon as I knew. They signed me off for 3 weeks in November. My midwife now wants me to be signed off sick until my maternity leave starts (7/3/16) and I'm still on 6 months probation, will this affect my contract? Will I loose my job? I'm physically struggling now and my midwife said I am doing far too much and putting too much strain on myself and baby. Will my work look at it this way or have no sympathy atall and just terminate my contract? I'm so scared. Thanks