Will "Unauthorised Absence" from School affect anything?

I am in Year 10 at school and I am going on holiday during term-time for one week (5 school days). The Headmistress will not authorise my absence during this time and it will go down in my records as "Unauthorised absence". I have a high attendance at school (just over 94%) and it is at the end of the academic year, I have made sure that I am not missing any exams or coursework deadlines. My question is will it affect anything like applying for college, or could my parents (or I) be punished? Is "Unauthorised absence" the same as truancy?