Manifestation

I’ve been practicing manifestations recently and I think I’ve become decent at receiving what it is I want to manifest. However, as of lately I’ve noticed that I’ll suddenly have a “fearful thought” jump into my head while meditating, and I’m wondering how impactful having a “fearful thought” is to what I’m trying to manifest. Is it possible to accidentally manifest my fear when I’m in that state of mind? Is it possible to counteract the unwanted manifestation? What to do with unwanted thoughts?