I think a coven of witches are putting spells on me, is this a delusion? i find things like tape on my doorstep from the spells they have cast.

A delusion is: A belief that persists in spite of evidence to the contrary. We humans are very good at false perceptions, false interpretations, miscalculating probabilities, & false conclusions. The most common error is to look only for confirming evidence. Look for evidence that could prove your belief is false. What other explanations are possible & which are most likely? Discuss with others.