My wife doesn't seem to be happy to be pregnant?

Being pregnant in the first trimester myself, I don't think it's that she's not happy, I think she might just be afraid to get attached to the idea yet, since the chances of miscarriage is very high in the first trimester. Also, she might be wanting to wait for the scan to make sure that everything seems to be going okay, that there's actually a baby in there (seeing is believing, especially for my husband), but she might also not be feeling well. Pregnancy hormones do crazy things to your mood and your fears. She might just be cautious right now and wants confirmation from the doctor before getting attached.