I got the perk to, but once I enchant it once it just disappears from the menu.

Select 2 enchantments you want then enchant,you do not have to do it twice separately.

Well I'm glad they made that clear. So now my gear is screwed?

Basically, yeah, you'll need to make new items

You cannot enchant items that have pre-existing enchantments on them that you didn't make. For example, I can't buy a Ring of Alchemy and then enchant it to Fortify Magicka.

You can only enchant fresh items...anything with an existing enchantment can't be further enchanted.

@OP: Are you sure you have the perk? It's hard to miss being able to double enchant something as the menu displays: Item:Enchantment:Enchantment:Soul Gem, and those highlight with the selection when you do pick it. (Apologies if that seems like telling you to svck eggs, but the actual display is down on the right hand side of the enchanting menu).

no hes right i did alot of enchanting and anything that you bought or enchanted before you got the perk cannot be enchanted again the only way it works is when your first enchanting an item