If I had to guess, I would think you are the type of person who plans things way ahead of time. If you are, than my best advice is a deep breath, add some Bob Marley to your Ipod, smile and relax a bit. It is very easy to over analyze every bit of the early sobriety process and it can really get the best of your personality without you even realizing.
The 1st week is a rush of emotion and anxiety for anyone. In reality though, and I always have looked at it this way, the 1st week is no different than any other week going forward without alcohol.
There will always be embarrassing pictures from the past, stories brought up in social settings, etc. In moving forward I would just laugh them off and don't let it get to you. The past is the past and it is something you cannot escape.
Anxiety about friends leaving you....Well this one is taken differently by everyone. You sound like you are smart enough to know exactly the people you will already see less of like I was. There are friends and there are drinking friends. My real friends absolutely support me and anything I do. Real friends show up when you are in the hospital. Drinking friends rely on their other drinking friends simply for the social aspect of nights out and drinking. These same personalities find a new drinking friend the same day you tell them you are making changes in life. If anything I found it humbling and humorous to experience.
Your parents ever tell you real and true friends are hard to come by? Well, score another point for the parents! haha
Regarding "focused on trying to make people believe that I am okay. Well and better without the drink.". This one is easy! Focus on yourself for the next 6 months and everything will fall into place seamlessly. Unfortunately anyone you feel the need to make believe or convince will likely not be around much anyways in the future.

Realizing within yourself that the change is good and positive will come soon enough, I promise. It will be one of those "light bulb" moments lol For me, about 3 weeks into my sobriety I was with friends for a pool bbq and having a wicked good time. I had a moment when I was able to think, take note of my surroundings, and just laugh my ass off! I realized I was having the time of my life at something as simple as a pool bbq with friends and I was dead sober. Best advice is to get out and live life, be happy, and do things you would normally turn down while drinking. It all comes into place as long as you stay motivated and positive. I am closer with my friends and family now more than ever because I deleted alcohol.
-Matt

Great job on Day 4! Don't worry -- it gets better!

My experience was that the first week I was withdrawing physically from alcohol. This process affected me physically and mentally. I had a lot of anxiety during the first month -- anything could trigger it -- though it times it just felt like an ever present "hum." I think one of the reasons that I drank was to relieve anxiety and, while it was a temporary fix, in the long run it made me anxious. I did not even realize this until I had stopped for a while and felt the anxiety gradually lift.

Your #4 (Occupied on EVERYONE ELSE but myself) Is something I would try to change. Now, in early sobriety, is a really good time to focus on YOU, take care of YOU. If you find FB to be stressful, take a break.

I had a transition when I quit -- for a while I was a drinker who was determined to not drink, then I became a nondrinker, if that makes any sense.

Keep it going!

Anxiety is very typical when you first quit. You don't have the drinking crutch to fall back on. By making the commitment to quit shows me you are focusing on you. We tend to blow things out of proportion at this stage.

A couple thoughts. Most people don't really care about you unless they are real friends in which case it will be a cleansing of your social network. That's a good thing.

You don't need to make people believe squat about you deciding not to drink. It is none of there business. Don't feel you have to justify it or defend it.

Regarding your last question. Sometimes it does happen over night and other times it is a gradual realization. Either way as long as you stay grounded and focused on what is important in your life everything will be fine.

You are sooo lucky and show a maturity to admit at a young age you have a problem. You are very lucky as life could and would turn in a very different direction if you continued to abuse alcohol.

Great job on day 4!