Can raising voice or being emotional hurt baby at 18 weeks pregnant?

No: emotional stress in general isn't something you need to worry about. We all have bad days and get upset or sad and sometimes lose our cool. While it might create drama in your life if you do it too much, which may make home life difficult for your child as he/she grows up it isn't harmful in general. Its more of an issue if you harm yourself when upset, refuse to eat or drink, or suffer abuse.