I find that the more I increase in knowledge, the more isolated and lonely I feel from people. Is this normal? I don't enjoy this at all, but I don't want to go back to being ignorant either.

‎Yes, the Prophet ﷺ‎ said Islam began strange and will return strange, so glad tidings to the strangers (Muslim), and the scholars explained them as those who are righteous when people become corrupt. Do not withdraw from people, though. Shaykh Ibn Baz said mixing with them, advising and teaching, is the Sunnah, so seek out righteous companions.