Check my automotive solid-state power switch schematic for mistakes
Your MCU may put out 3.3V, but D1 drops ~0.5V so the FET Gate will only get ~2.8V. According to the datasheet it doesn't fully turn on until the Gate reaches ~3.25V. In the graph below I have marked where you will be on the transfer curve - not even half turned on (and this only shows the typical response. Some units will be worse). 



To efficiently switch a high current load the FET must be fully turned on. Your 3.3V MCU output is barely enough even without a diode in the way. You should add a level shifter that increases Gate voltage to at least 4V.