Will database replication increase the size of the replicated database?

First thank you for your time. We have a SQL Server database that was assigned to be replicated. the original size of the database was 5 GB for the datafile, not the log file. Now after the replication the data file is 4 times bigger around 19 GB. Any pointers to see what could happened will be appreciated. I know sql as developer and some little management but nothing about replication. The performance of the database has been damaged very bad so I am trying to see what need to be done to improve it. I do apologize for my English as well.