Divert your attention to other things or use stimulation therapy. For example, if you study more and work more during this period of time, you won't think about other things when you are mentally exhausted, and the feeling won't be very strong. You can also watch more horror thriller movies, see some more disgusting pictures, see more, you will not feel the black hole and other things terrible, because you know the world has too many more terrible things ~ ~ ~ ~
In fact, this nausea or fear is precisely from the fear of avoidance of the mentality, boldly go to face it, experience it, a period of time after the gradual adaptation and accustomed to it, the main thing is that this image stimulates you to think of other things, so you can not think of other things. The main thing is that this image stimulates your psyche and it takes a while to get used to it, it's okay.
If the stimulus is really very deep, such as after 1-2 months is still very strong, you should go to see a professional psychiatrist.