Fatigue and pregnancy

Hello, I wonder of anyone out there can give me a bit of help. I am over eight months pregnant and for the last two months I have been feeling terrible. My midwife said it was to be expected being pregnant with a third child so close to my last child, but this is not normal pregnancy tiredness. I know the difference by now. I get up early for the school run and by the time I get home I desperately need to go to bed. I can’t wait for the youngest to go for a nap as I need to sleep. I can’t do anything, cook, clean washing I just feel dreadful. I read that you feel better during pregnancy and that relapses can stop, but does that include fatigue. Can you have fatigue without it being a relapse? I have tried to contact the ms nurse but until now have had no luck whatsoever in getting a straight answer. I hope some one can help me, I don’t know how much more I can take of feeling so lifeless like a ragdoll.