Nesting...

So I have been told that 'most' every pregnant women go through this nesting phase. so i am 37 almost 38 weeks and i have yet to feel this nesting. i feel that this does not exisit with me. i don't think that this makes me a terrible mom. but wonder why i am not going through it. why don't i have the urge to clean the house? why can't i get enough energy to clean the house? i just get so sleepy after cleaning one room if i even get this far.