My relationship with alcohol

Why can’t I just drink like a normal person ? Last night I went to the beach and grabbed 3 beers and all of a sudden , I needed more , went to the liquor store bought 2 more and went home and then needed some more , went out around 3 am and got another 2 and I am fucked up now . Why can I just drink like a normal person ?

Do you guys have any practical tips for stopping and knowing your limit ?