Thank you for all the comments, much appreciated.
People who do mindfullness/meditiation, how did you start? Should I be looking for classes or something? And is there a difference between the two?
It's difficult to explain but Mindfulness is basically about bringing your attention to the present and thinking on a moment to moment basis rather than dwelling on things that happened yesterday or last week or 20 years ago or panicking about something that might happen next week.
Meditation is similar in many ways - about clearing the head from external thoughts and learning to control breathing and thought processes and help purify mind and body.
I started using classes as there was one easily available to me but there are many books out there which usually come with CDs to help guide you through the process or Amazon have guided meditation tracks available for MP3 download for 89p if you want a cheap experiment. There are 10 or 15 minute guided meditation MP3s available which is probably where I would start (some last for hours but you would need to practice for a long time before you could meditate for that length of time imo.
I suppose a class is good as you have somethere to ask and guide you through it if you're struggling but the books and CDs should work fine too but it does take practice.
Daver suggestion of yoga is also an excellent one as it brings fitness benefits as well as mental benefits.