HOW DO YOU PICK A PROTEIN?

So I have a date and I am freaking myself out about protein. There are SO many different kinds and they all say they are for different things. What am I looking for? Low carbs? No sugar? How many carbs is too much? How much protein per scoop do I want? When can I drink protein drinks? How about the clear looking ones like isopure and cytosport h20 water? Can I have those right out of surgry on the clear liquid phase? If so should I buy some before or after even though my tastes will change? Does it have to have no sugar? I have SO many questions about choosing proteins and foods after surgery. Is there a place where I can get all this information?

Can you tell I'm freaking myself out??

 I am using a protien powder from walmart, low sugars, high protien, low carbs. its less exspensive than GNC, i can buy 8lbs from walmart for 58$ the 70$ for 5lbs and gnc. im soooo full from it right now.

 Below is a link to a place that carries single servings order a bunch of dif flavors to try!
Nectar and Inspire are my favs!!!
http://www.stvincent.org/St-Vincent-Womens-Hospital/Medical- Services/Womens-Health-Boutique/Bariatric-Products.aspx

I study a lot of this stuff and the best would be Whey Protein. It is a clean and health form of protein and also Whey boost the immune sysyem. It helps build muscle as well.  Try Designer Whey Protein I feel it is the best because it is backed by clinical research. Do a search on it ..the chocolate  shake is a really good drink