Here's some author suggestions,
1)Write about every emotion you feel and convert it into a manga or story, even if you feel nothing. Nothingness is also a feeling, like an empty black void. I usually describe it with black holes.
2) when you feel like there's nothing on your mind to write down or draw, just do something small it doesn't have to be a masterpiece and that slow progress builds up your motivation. Like a small skit or comic that's simple and move on slowly.
3) mess around with colors, words, everything just test new things because it's all in your hands and you can literally write/draw whatever you want!
Good luck 💜