help a stressed girl out

Ok so I'm applying to university and I went for my interview which I don't know how it went it's hard to tell at this point but I'm so stressed because I've actually given the course a thought and I don't actually know whether it's for me I keep changing my mind constantly, I just feel so much pressure right now. I'm 18 years old and on my last year of further education. Did anyone else feel this way and what advice can you give me?