Low placenta

Claudia • Mummy to William James 8th March 2015
I had some cramping and bleeding last week which has continued into this week as well. 
​I went to the hospital and had a scan, blood test and urine test. And the scan showed them than my placenta had not risen up yet. I am 16 weeks and the baby was ok moving round and the heart was beating. 
​I am just unsure what a low placenta means. They didn't really explain it. 
​They just said at my 19 week scan that they would check to see if it had risen. 
​Has anyone else had this? They put me on bed rest for a week and told me not to do anything strenuous. 
​It is my first baby and I don't really have anyone else to ask. And I don't really want to google as it just makes everything ten times worse. 
​Thank you