A simple (and quite fun) idea to help you and your child distinguish between your role as a Mummy and your new role as Home Teacher is to use the ‘fun hat technique’.
At the start of each day my child chooses a hat for me that I will wear when I am being his teacher (we call it the ‘teacher’s hat’). I then take it off when I am being Mummy.
Although it might seem a bit silly at first, I find it helps to put me in the teaching mind-set and ensures he knows when it’s time to focus on his learning. As a bonus he also finds it very funny!
Why not give it a try and see if it helps? Of course it doesn’t have to be hats. Let me know in the comments if this has worked for you!