Firebird database with problems

I have a new Firebird Database, deployed less than 60 days, until then little used, in one day its size was 40 Megas, in less than 6 hours users complain about slow system, when verifying the Database is at 126 Gigas. How is this possible, what can be happening? Any solution? How to check for possible errors? When analyzing this information apparently it is only in a table, which logically I can not open due to the amount of data.