That does sound abnormal and not something I've heard before, and I've known many (including self) who used alcohol and weed as teenagers. The drunk/high effects should not last beyond about 6 hrs maximum.

Is it possible that she just sort of "cracked" emotionally, and it's unrelated to the drug/alcohol use? Are you sure she hasn't been continually drinking or smoking since the first time? Have you talked with your friend and asked her how she feels? If she does feel really out of it mentally and there's no other cause besides the first time use, it may be worth getting her to talk to a doctor. In my experience they're usually pretty discreet, even when drug use is involved.