What would you do if you were in my position?

So I spent a fair bit of money on coming to Scotland to see my best friend at Uni. Hoping to see some of the city grab some lunch or do a bit of shopping I text her . She wants to stay in bed because she's got a cold . I get a taxi there and she wants to stay in bed all day. We go down for dinner and she spends most of her time talking to her love interest. After dinner I thought it would be good playing articulate with her other friends.. Turned into one of her friends having an episode. She left me from 9pm until now in her room bymyself I couldn't even go offer advice as I wasn't supposed to know what was going on. She comes back the girl seems fine smelling of beer, and my best friend, who had looked down at me for going out with someone who smokes , I found out has started smoking, heavily. And has done throughout the night. Whilst she left me here. Alone. I came to have a good time, and it seems that she's completely changed. I really want to go home today but the train would be an extortionate amount. What do I do? I apologise for the mass of text as I'm on my phone. Thankyou!

Sorry, but it's got to that stage of the night where I automatically feel the need to reply to any thread titled 'What would you do if you were in my position?' with 'Sit down.'