I totally sympathise with you, I worked 32 hours a week on my last pregnancy in a special school, (leither loads of lifting and bending with the wheelchairs, or being pushed, pulled and sat on by the children with challenging behaviour). I worked up until 2 weeks before the birth, didn't complain or ask for lighter duties, but I SHOULD have. I used to come home shattered, depressed and irritable which wasn't fair on my 8 y/o or o/h. Even though we really can't afford it I have given up work this time, but still feel shattered all the time so goodness knows how I'd be if I was working. Your body is asking you to rest, take it easy and slow down, but in your head you don't want others to think you are taking advantage of being pregnant. Do try to come to some sort of arrangement with your boss, maybe you can avoid certain tasks which are strenuous or have a 5 minute sit down when you feel really worn out, as long as you've discussed your reasons they'd be mean to say no. Some people forget what it was like to be pregnant and say 'I was full of energy all the time and felt great' well lucky them!! Nobody feels great every single day I'm sure, so look after yourself, you won't get thanked for trying to be superwoman, you just get more work piled on you for being efficient, do your best, but when you feel the strain, take time out that's my advice! Sorry to go on, o/h on x-box so I'm bored!!