Sree Sree Guru Gaurangau Jayatah!
A sincere soul who wants eternal welfare should suppress the flow of bad thoughts and should increase the flow of good thoughts. Spiritual practice means struggle. When good thoughts predominate then one has crossed the unsafe region. If one gets the association of superior vaishnavas, then the mind will be changed. You should remember that you cannot get spiritual eternal welfare and so-called material gain by your own capability. Take absolute shelter of Supreme Lord Sri Krishna and His devotees and become peaceful. Prahlad Maharaj was completely surrounded by the anti-devotional demoniac persons but he never became unbalanced or gave up bhajan because of his absolute reliance on the Lotus Feet of his guru Narada Goswami and Supreme Lord Sri Narasimha Deva. Go through the holy life of Prahlad Maharaj narrated in the seventh canto of Bhagavatam.
You should remember four Narasimha mantras while going to bed and just after rising up from the bed and also if possible remember Narasimha Deva, Panchatattva and Mahamantra before going to do something at daytime. By remembrance of Narasimha Deva, Panchatattva and Mahamantra, disturbance of demoniac creatures and all troubles will be removed. But you should do it sincerely with firm faith.
--- Jagad-guru His Divine Grace Bhakti Ballabh Tirtha Goswami Maharaj