After we graduated high school, my best friend and I have drifted apart somewhat. Now I've met her again after our first year of college (we're going on vacation together). She's changed drastically in the past year and seems out of control. She's almost a year behind on academics, binge drinks weekly, smokes daily, doesn't want to tell me about her drug use, is broke despite getting a ridiculous amount of money from her parents and owes most of her friends 100$+ (and is behind on her rent). She also seems a little bit iffy on her decision making: for example, she spent 300$ at a single store when we went shopping together, then revealed to me that she was now broke and literally had no money left to buy food for the next two weeks (she resolved to mooch off her roommate instead of, I don't know, returning the clothes that she didn't really need in the first place). She also used to talk about getting a boyfriend; now she just decided to lose her virginity to some random guy she met since "he was a guy and he wasn't too bad-looking". She's also started dieting somewhat excessively in my opinion- she had a phase where she was bingeing a lot, then she decided to lose weight and stopped eating every other day, then she decided skipping breakfast in addition to that was the solution and now I don't know and I'm not sure what to say without sounding preachy.

I've held my tongue because I don't want to be judgmental. It's just a very jarring contrast to someone who didn't smoke, didn't do drugs, ate normally, was very passionate about her academic future, always had more than enough money on her bank account and had only ever kissed a guy ten months ago. She also doesn't get along with her parents anymore (they had some sort of falling out, I think about the money). I don't want to piss her off by sounding like them, but she's starting to scare me. It also doesn't help that we've sort of grown apart- I won't go shopping with her anymore and everything else ends with her "-and then we can go out drinking", which I couldn't fit in before finals. (She ended up blowing off hers to randomly go to Barcelona)

Am I just overreacting? If not, how can I bring this up without coming on too strong? I tried hinting to her that making a budget would be a really good idea, but she shrugged it off and said that she was just going to see if she could get a part-time job to make ends meet. (The money she gets monthly, even minus her rent, could support one of my more thrifty friends for three months). I really don't know what to do, or how to say that I would just love to throw some kind of intervention for her. How do I put this nicely?