Yes it is normal, when I frist got pregnant that was the only thing on my mind, and I didnt help I know a girl whop had miscarried 3 weeks before I found out I was pregnant. I talked to so of my friends who know the girl. They told me that best thing I could do was not worry about it. Just tgo on with my days and try to think of something else. It was hard a frist but it worked. I am now almost 5 months and my baby is fine and heathly.