Dreaming of a thistle reflects the dreamer is going through a time of bad mood. If we tear off the thistle in the dream, this situation is accentuated. If we are able to avoid the damage form thistle, then it is a good sign.
Dream dictionary: Thistle dream meanings
If you dream of the thistle, then it indicates your need for security. Probably you made some obstacles and walls to protect yourself from others, therefore nobody can come to you and help you.