nervous spells

My husband was driving us to a friend's house and there was a lot of traffic and people who obviously didn't know where they were going. I started to get really nervous because there was a car trying to get into our lane. My husband decided that he was going to keep driving instead of letting them in. I got nervous because all I could see is us getting into an accident and me losing our baby. Am I being too emotional? I'm a first time mom only 6 weeks along and there is a history of miscarriages in my family, it makes me really nervous to do anything. I just want to be calm and not get into fights with my husband over something stupid. Just curious if I'm overreacting.