35 weeks + 1 and absolutely shattered

So I have 4 weeks and 6 days left, if i dont go over. I am so exhausted I literally struggle to get out of bed. On iron tablets and no improvement. The 2nd trimester I had loads of energy which makes this 3rd one even worse. I am working until the 14th October, due date is 1st November and don't know if I can manage. Meant to give work 28 days notice to change my leave date but obvs that has come and gone but will ask if I can leave on the 7th when I am in tomorrow. Wanted extra time off with the baby but I'm sure me being rested is better for him. Plan to take the full 39 weeks mat leave and hope to go back part time. Anyone else feeling super shattered?