did you calibrate your unit.
I am not expert but I will tell you what I think I know.
The first thing I would do even if you did I would re-calibrate it, the instructions are in the manual but to do so, flick you flight mode switch up and down 6-10 quickly, when you get done with that a blue light should appear in the LED indicator, holding the craft lever, spin it clockwise about 360+ degrees until the light changes color - Green.
Next hold the craft vertical and do the same until the green light changes to white. At that time the unit will be calibrated and put it back down normally. Give it about 5 sec, I usually have been disconnecting the battery at this time, however in the past there have been times where I have not. It seems to work the same either way.
Two other things I would check is to make sure you props are spinning in the proper direction, as in the diagram shows in the manual and software assistant. and make sure when you go to take off the wk-m is in att or gps mode and you should be able to determine this by the LED cycle. It first does your GPS flash (1, 2, or 3 quick red flashes) followed by one of three results. no light which indicates your are in manual mode, amber light telling you are in att mode, or a blueish white light letting you know you are in GPS mode.
Just for fun before powering the motors I would switch to manual, see the chance in the light, then put into att or gps, just confirming mentally that you are in the right mode.
I also have had something like what you explained happened to me before, but since I now go through a small check of everything before powering motors, my issues have seemed to calm down some.
The other thing I would say also is, stay heavy on your sticks during take off and landing. Like a real helicopter when the craft starts getting light and the littlest input can make a huge difference. Every time during takeoff and landing when I am hitting that light zone, I will sit on the sticks waiting to make very little compensation to help the craft until it gets its bearings to say.
The zone between being light enough to move tilt the craft and liftoff is very critical and something where I believe a person controlling the craft needs to be on their toes. Once the craft is off the ground then you can start adding more power and being more aggressive.
I know you said you were doing what the setup manual was telling you, I would go back into the software assistant and make sure in the flight mode area that when you put the flight mode switch on you transmitter into the proper mode that in the assistant is seeing it and your mode slider in the flight zone indicator is turning blue. You can have the slider move to the proper zone but if that zones indicator in the slider reference does not turn blue then you are not properly locked in.
If you controller has mixes, or you programmed it for some, GET RID OF THEM.
Best of luck Jack