Baby dropping WAYYYY early.

I had a doctor appointment today and she checked me because I have been cramping last night and this morning. I'm 28 weeks and she said I'm a 1 and she is EXTREMELY low. She put me on bedrest but said she knows it's going to be really hard for me to do since I have a 3 year old and an almost 2 year old. Anyone had anything similar happen to them. I had preterm labor with my last one but she said she's worried where she's already so low. She said to come in if I feel ANYTHING because I can dilate fast with her being as low as she is.