Circuit for amplification and protection against input inductive spikes
In my toolbox I don't have a negative voltage rail, so I'm planning on
  using an op-amp to invert my positive rail into a negative and use it
  to rail other devices.


No, no, no this won't work. An op-amp produces an output voltage that is limited to values within the range of it's own power rails. If you wanted to generate -5V by using an inverting amplifier, the op-amp would need a negative rail of between 5.1 volts and 8 volts.

You can't expect an op-amp to simply generate negative voltages like that.