I would connect the HC05 to a software serial port or extra hardware serial port if one is available and save Serial for program upload, debugging and monitoring program flow and variable values, at least while developing code. Having 2 things (HC05 and serial monitor) connected to the same port can cause problems.
You might want to have a look at the serial input basics tutorial to see how to make up data packets, receive and parse data packets reliably.
What is sending the data?