32 weeks struggling with work

Rebecca

I'm 32 wees and 2days and really struggling at work. I'm seated most of the time but I work in a bakery and the heat is unreal. I'm also not sleeping till gone midnight nearly every night and getting up at 5am for work. I'm due to leave in 3 weeks but not sure if I can last that long, but work are not being understanding and won't let me take any annual leave so that I can leave work early.... Should I just go off sick? I feel bad because I feel like I should be working for longer. 😣