Assuming you have two inputs (direction and speed) mapped to their corresponding keys, you could simplify your Animator FSM by using a 2D Freeform Cartesian Blend Tree: left goes to direction -1 and rear goes to speed -1 (or whatever you choose to call your inputs).
My guess is your input is not producing the desired values. An 8-way movement matrix (plus Idle) should be like this one:
[-1,1][0,1][1,1]
[-1,0][0,0][1,0]
[-1,-1][0,-1][1,-1]