I've just started a new Undead Warlock and for some reason can't get Herbalism as a secondary skill. Is it a secondary skill? I have enchanting and Alchemy as primary skills but would obviously need Herbalism for Alchemy. I've visited Faruza in Brill just outside the Undercity but she doesn't give me an option to train my Herbalism. Where do I got to get herbalism as a skill?