Hi Nicole, welcome to Talking Sober! 
It’s such a painful thing when we are not the person we know we should be. When our relationship with our addiction becomes more important to us than our relationships with the people who matter to us. We plan our whole lives around our addiction. And in the end, we alienate ourselves from our loved ones, and we hurt ourselves. We feel regret.
You are not alone. Most of us here have been in your shoes.
You say it’s a choice, and in a way it is, but it’s a choice in the same way a river “chooses” where to flow. If you took the Nile River, or the Mississippi River, or the Amazon River, and said, “Hey, you should flow a different way!” the river would say, “What are you going to do about it?” and would continue to flow along the riverbed it has followed for its whole life.
The river water is you, the river bed - the path carved out by years and years of habits - is the habit, the thing that you flow through if you don’t take action to change it.
You say the choice to drink or use is a choice, and it is, but it is a choice in the same way a river chooses to flow on its existing riverbed.
To change the flow of the river, you have to build canals, levees, channels, aqueducts - you have to invest time every day to build the new river flow that you want to have. It is possible - it takes sustained daily effort, but it is possible.
The canal-building, the channel-building - that is your sobriety work. For some people it is lots of time on Talking Sober, for many people (not all, but many) it is involvement in a sobriety group (for example these ones: Resources for our recovery or these ones: Online meeting resources), for some people it is other spaces - or a mix of all these - but for all of us, it is daily effort to learn and live sobriety: to learn to “ride the wave” of natural, normal human emotions and life experiences (ups and downs) without numbing out in our addiction.
You’ve taken a courageous step today asking for help with your problem. Keep asking, keep learning, keep moving forward one step at a time, each day, and you will find yourself. You’re a good person - you’re a good person - and you deserve a safe, sober life where you can be your full self. 