How are you doing today?
I am so grateful that you are working on your sobriety path and have found this beautiful community.
Quitting is not easy and it will not magically make everything ok and bring immediate happiness. BUT it will provide all that and more if you stick with it. It takes hard work and patience.
I am sorry you are dealing with so many health issues too. The inflammation is a bitch to deal with and alcohol is most definitely a big contributor to that.
I don’t know what normal is cause not many people can actually moderate. I hid the excessiveness of my addiction and also appeared to be happy on the outside. We certainly can not compare ourselves with others as we don’t know what they may actually be experiencing. We know that we do not have a good relationship with alcohol and that is what we need to work on. Not even one sip - then we will be ok 
Life is so beautiful and fulfilling without alcohol - we just have to retrain our minds and learn to exist without this poisonous crutch.
Support is necessary in this journey. You have found us here. If you can join a support group in real life that will also be helpful. Maybe get a counselor to help you stay accountable.
Check out the following threads to help you make a plan and gain resources. This app is also full of many threads that will help you stay on track. The community is full of support and advice and guidance. Stay connected here and keep pushing through the rough patches (they do not last and will lessen over time) and you will be celebrating many milestones
What’s YOUR plan?
The early days will be hard and you will be Exhausted! The body is detoxing and doing its work which takes energy. Try to be gentle with yourself. Have a lot of non alcoholic drinks (i preferred la croix’s) and keep yourself busy with tasks/ hobbies. As you gain days in sobriety, you will start gaining energy and motivation. Your brain fog will lift and your body will start to heal. You will be able to enjoy fun time with the kids. Just hang in there friend and remember that by drinking will not make you the same promises (even if it gives you that immediate false energy and boost).
Small towns are hard as everyone knows everyone. Even then you don’t realize that you really don’t know anyone as we are great at hiding our flaws and addictions. If you don’t have a AA or other recovery support groups then please join an online meetings. Some run 24/7. You do not have to participate and can keep voice / camera off till you feel comfortable.
Just cause you sent in a rsvp does not mean you are obligated to go. Many people do not show up and then so many that didn’t rsvp do show up so it balances out. You have to look out for you. Your fiance is the groomsman and has to go and it is up to him if he feels like drinking and attending the reception. You can opt out of both or just do the wedding and spend the rest of the time on your own self care. Attending these functions in early sobriety is very difficult and boring as you are filled with FOMO and struggling to not cave into the urges. Do not put yourself through that torture. If you have to go then do as @Dazercat suggested and be prepared. A non alcoholic drink in hand, a space to go and rest if needed away from the crowds, a escape plan and us in your pocket 
Here’s to another day fighting the good fight 