I am exhausted

I'm 35&3 and I am absolutely exhausted. I wake up every hour at night as I'm sure you all are too either to go to the bathroom or because my back and hips are in so much pain. Then by around 3 every morning I'm up and can't fall back asleep. I've tried everything from teas to heat pads to a million pillows but nothing works anymore. I have an hour commute in traffic to work then an hour back in the afternoon. Multiple times I've almost fallen asleep while at my desk...I work as a reading interventionist at an elementary school and go back and forth between classrooms, my office, and taking groups. My plan has always been to work until I go into labor but now idk how I'm going to make it 4.5 more weeks. I feel so silly getting a Dr. note for being tired to miss this last month of work. Please tell me I'm not alone! How are you ladies dealing with it?