Pleased you're back and sharing with us. I hope that writing and reading here gives you a clearer picture of what's going on. A couple of things are worth bearing in mind at this stage, I think. Cocaine is an illegal drug and if you are arrested with it you face immediate arrest and potentially a prison sentence. In the eyes of British law it is definitely not "as socially acceptable as drinking" - it is a serious offence. You say you recently have a new job. What would happen if your employer knew you were doing cocaine?
The pattern you describe is going out with friends, getting very drunk and then going out looking for coke. I have a feeling you are not being discreet when you do this and this puts you in a risky position with the law, and indeed with dealers who may exploit you.
I'm really pleased that you're taking time now to look at how to make some changes. Life without drugs is perfectly enjoyable and if you keep sharing with us here you'll find lots of support, including from young people your age.