Placenta previa

I had my 18 week ultrasound today and they told me I have marginal placenta previa. I have had no bleeding and no other complications. If I have to go on bedrest I will loose my job and insurance.  I know the placenta can move up in the next few weeks. My concern is that I am a nurse and don't want to over do it but sometimes don't have the option to take it as easy as I would like. I work with children. Any onther nurses or anyone that has a physically demanding job have this happen? Any tips?