New Here - Getting back on track

Hi, I'm just new to this. Spent the past 8 months working in America. Between the 17 hour work days, crappy food, huge portions and being too tired to exercise... I put on about 2 stone. I am going on hols in 6 weeks. First holiday in 5 years, so I'd like to feel good again. I know what to do as I was quite fit and healthy before, so just need to stick to it and get rid of the extra weight. :-)