Start small and quick, 5-10 min max. If you feel like drawing more that's great, but log those 5-10 minutes even when you don't feel like it.
If you can't think of something to draw, draw what's in front of you. Sketch a glass of water, your phone, your shoes, a tree, etc.
And keep your tools to a minimum, if you draw digitally use a simple round brush, if you draw traditionally use just a pen or a pencil (no eraser though, it'll force you to accept mistakes and move faster).
That'll help you build the habit and get past the feeling that you need to create beautiful finished products every time you start drawing.