Data Deleted After a few days of being off

[A]

I'm new to Cassandra.  Trying it out to see if it will work for my upcoming 
project.  I created a test keyspace and table on my dev laptop.  Loaded it with 
some data on a Friday and closed her down.  Returned on Monday and looked up 
the data and it was gone.  The keyspace and table was there, but table was 
empty.  This has happened twice so far.
Help...
Thanks,Angel