I totally agree with AmandaErlandson,this person is asking for advice!!!!
Chances are,everything will go just fine with the pregnancy,it's NOT an illness,Mother Nature usually takes care of things just fine.(I had 3 kids so birthing is not that big of a deal)Sometimes another sow will actually be helpful and no,they don't make a nest since the pups are able to run around right after birth.There are some videos on youtube of
cavies giving birth,just search "guinea pigs,birth" then you will know what to expect