Yeah, you are an addict. "Just One" doesn't apply to us. Sooner you realize this the better off you will be. Withdrawal sucks, but you are stronger and smarter, so don't give in.
Answers to your questions (Sort of)....
1. Blah, Blah, Blah....There will never be a convenient time to quit. Every trigger you encounter while quitting will mess with you. You will get past this, but it will take some resolve on your part. As for the agression: go running, get a punching bag, etc.
2. No reason to be worried. When I quit, I felt like someone close to me had died. I felt empty and like I had no direction. It sucks, but things get a little brighter day by day. Focus on the good.
The games that this addiction plays on us are terrible my friend. You gotta remember that you are the strong one and YOU are in control. You do have the power to quit, never doubt that. Let me know how I can help you.