K.W.
Hi D.,
There have been some bugs going around, but I wouldn't rule out pregnancy. I've now known 3 ladies that have taken pregnancy test to have them come back negative when indeed they were really pregnant. One of these ladies even went into the Dr for them to say maybe it was mono.
It wasn't till 7 weeks in or more that they finally concluded that she was pregnant. I say go ahead and take care of yourself as if you were and be prepared if you arn't. Good Luck!
Sincerely,
K.