Thank you to everyone for your kind replies.
Its day 2 and I have finally gotten over the hangover. When I was having a shower the thought came into my mind whether I was overreacting , but I completely blocked it out. I have tried giving up in the past but somehow always come back to drinking casually at first and then going back to normal, but this time I just started thinking about all the bad things that alcohol has brought.
This friday is my birthday and I am going back home to meet friends and family. I know they have organised a party and there will be drinking, I have made up my mind to inform them that I have given up and this will be the real test.