"Serial1" in Arduino Micro is Physically connected to TX and RX pins (TTL), "Serial" is just a "virtual port" which you can read using Arduino IDE's Serial Monitor, thats why arduino micro is little different from another such as nano or pro mini.
if you use Serial and Serial1 you can aproach this advantage and upload code using USB and make a connection thought bluetooth (using HC06 connected to physical pins) without disconnect the USB cable and powered both devices (micro and bluetooth).
If you can't upload code to your micro sometimes, press micro's reset button then release it and press upload button in Arduino IDE's.
"virtual port" sometimes needs to restart and connect using USB.
This is from Arduino's Documentation Website:
"...Serial: 0 (RX) and 1 (TX). Used to receive (RX) and transmit (TX) TTL serial data using the ATmega32U4 hardware serial capability. Note that on the Micro, the Serial class refers to USB (CDC) communication; for TTL serial on pins 0 and 1, use the Serial1 class. "