Circuit to enable / disable VCC and GND
Your circuit needs a small modification: connect the low-side n-FET gate directly to the control input, as follows (simulate it here):

Choose appropriate pass FETs, or even parallel multiples of them to get the desired current handling you seek. (Yes, it's ok to connect MOSFETs in parallel.)
Here's an improved version that counteracts the effect of the FET body diodes (simulate it here):

The back-to-back FETs prevent backdrive from the load.