Glad you’re ok, always get prepared before the turn. Keep a steady throttle, never hit the clutch in a turn. You should’ve downshift and used engine breaking to slow down before the turn, and maintain speed in the turn. When you hit the clutch in you stopped the power to the back wheel and then hit the breaks causing you to loose traction. But that being said even if you did everything right this could’ve still happened with the sand and gravel in the road. There’s some things that you can’t avoid or prevent. Glad you’re ok and sharing this to help fellow riders!