@matthewclso, you can not go on like this.
Using the Arduino Mega 2560 board at 3.3V didn't ring a bell before, but it is not possible.
The Arduino Uno uses a ATmega328P which will probably run at 3.3V, although not according to the datasheet.
The Arduino Mega 2560 uses the older ATmega2560, and that chip must have at least 4.5V to run reliable.
If you have already connected digital pins (with 5V HIGH level) to the AD0 of the MPU-6050 chips, you have to throw them away. All of them.
I think you can create one object and use whatever sensor is set to 0x68.
It depends on the library if that will work, and I don't know which library you use.
I also still don't know how many data samples you need per second.
Can you tell what your project is ? Why do you need 14 accelerometers/gyro sensors ?