First - take a deep breath. Now, go make yourself something nice to drink.
About beverages. Go with Dina's advice on water and jeez, it's vacation, if you really drink a lot of soda, just fork out the money for a soda card, if you don't, then you're looking at less money (IMHO) than it's worth to lug all that with you. If you are flying, you don't want to risk it rupturing in flight. If you really want to be economical, then buy a couple bottles of soda at each of your ports. It will be about the same price as in the US and you can bring a few bottles at a time on board.
Clothes - well, I'm one of those people who can do a two week cruise in my carry on, but try this. Lay your clothes out on your bed by day. Do your evening clothes first. Now, see what you can mix and match. Can you wear the same skirt or pants several nights? Switch up tops and bottoms for a different outfit? Now see if any of your tops can be worn in the daytime as well. Can you wear it in the evening then later in the week during the day?
Over the years I've accumulated a batch of cruise clothes based on packability and versatility. My "formal" is a long black knit skirt that takes up as much space as my hairbrush and a top that is about the same.
Shoes. Now here's a whole thread in itself. I take tennis shoes (wear them on the plane/on board since they're the bulkiest), I take a pair of sandals for casual wear and pool side and a pair of black heels that I wear every night.
Toiletries. Buy travel size items at the drug store or small packs and put your products in them. Pharmaceuticals I transfer to small zip lock bags. I've had my pharmacist do me a set of labels for them to avoid problems. There will be soap and shampoo onboard and since I'm not fussy about either I don't pack them. Since you are sailing Carnival there is always a sample pack of items in the room and usually includes a razor.
The ship board shops carry items you may have forgotten, as do all your ports of call.
My advice to people is to lay out all your clothes and then pack HALF of them. I promise you, you won't need as much as you think.