My girlfriend drinks heavily, and it's affecting our relationship.

My girlfriend (36 years old) and I (22 years old) have been together for about four months. When we first met, she was working as a machinist with long 12-hour shifts. About a month into our relationship, she decided to switch back to her old job as a barber. While she's focused on building her clientele, I've noticed that with her new schedule, she tends to go out 4-5 times a week and drinks heavily each time. On New Year's Eve, she expressed a desire to spend the evening with me at the movies. Unbeknownst to me, her college friends were in town, and she decided to go out with them before joining me. When she finally returned home, she was quite drunk, slurring her speech and being a bit argumentative. I tried to brush it off, but it still upset me, leading to a minor disagreement. When we got to the movies, she fell asleep almost right away, which I found disappointing since it was our first New Year's together. However, I recognized that her friends were visiting, so I chose to let it go. A few weeks ago, she invited me over to make dinner (spaghetti) while she was at work. I agreed and went grocery shopping in preparation. When I arrived, I tidied up a bit and waited to start cooking until closer to when she was due home. She was supposed to finish work around 7 but didn’t come back until after midnight. She explained that she had to drop something off at a friend's bar and ended up staying longer than expected. Because I noticed she was still at the bar through our shared location, I opted not to cook for her. When she finally came home, she was very drunk and immediately got upset upon realizing I hadn’t made dinner. She stormed upstairs and slammed her bedroom door. I felt disheartened because this seemed to be a recurring situation. I tried to talk to her, but she was too inebriated and confrontational, so I went back downstairs, made her spaghetti, and then slept on the couch. Later that night, she sobered up and came downstairs to apologize. I forgave her and tried to move on. Last night, after work, my girlfriend went to play pool at a nearby pub and stayed until around 11:30. She called me on her way home, slightly intoxicated, and immediately started making rude comments. Frustrated, I told her I needed some space to sort through my feelings since it was becoming overwhelming. The next day, I avoided her calls and texts until she reached out again after leaving the pub, apologizing and expressing regret. I called her to discuss what was bothering me, but she said she wanted to have that talk later. I agreed and checked her location, which confirmed my feelings—she was at her friend's bar again after work at 11 PM. I texted her to reiterate my earlier concerns, but I was left feeling confused and drained. This is a lot for me, but I do love her. I'm unsure how to approach her about this without it leading to an argument. Any advice would be appreciated.