I had something similar happen. Someone showed me something particularly…vile at one point. And no matter what I did, it just kept getting stuck in my head. The harder I tried not to think about it, the more I did. Here’s what helped me: you’re human. It’s impossible for you to have positive thoughts all of the time. Sometimes you’re going to have negative thoughts, and there’s nothing you can do about it. Instead of pushing them away when they come up, and trying to think positive again, you could try sitting with the negative thought. Observe your reactions to it. Try to stop reacting to it (Rey might say to try to feel neutral about the thought first; which would look like reminding yourself: “hey man, I’m human, this is a negative thought. I’m going to have them. No big deal.” And you feel it. You breathe through it, so your body feels safe. And eventually it will evaporate. Everything passes. It seems like you’re nervous your negative thoughts might affect your manifesting. Maybe try sitting with the worst case scenario: I might not get what I want. That’s worst case. Oh well. Then you might not get so upset when the negative thoughts come. It’s your feelings/your emotion/your reaction to the negative thoughts and the stress of it attracting something you don’t want. So if you’re more neutral, “hey I’m human, this is going to happen.” It might get easier. Then you can try to see the negative thoughts as a cool little spiritual challenge to fortify your mind when they come up.

@Erhard H. Thank you very much. I look forward to doing the same. (: