Is it necessary to neglect one's religion or to continue in isolation to maintain adherence to religion and avoid bad language, in light of friends distancing themselves because of this?

As long as you are characterized by virtuous morals, you are upon immense good. Your feeling of loneliness is better for you than the companionship of someone who corrupts your morals and your religion. You are in a house of trial, and perhaps this loneliness of yours is a test of the sincerity of your morals and the steadfastness of your religion. Be patient with the loneliness you find, and seek out a righteous friend whose companionship will benefit you.