Could my wife be pregnant?

no. tell tale sign is she had her period. it is HIGHLY unlikely she had her period and is pregnant, it happens to very few women but mostly it never happens. sorry if you wanted a baby but it just isnt here yet. it is probably just stress messing with her hormones and thats probably why she is going through what she is. after she takes the test have her go to the doctor. she might need some anti anxiety meds to help her deal with her cousins loss and school. good luck