Here are some recommended organisations for you depending on your country of resident.
United Kingdom
www.childline.org.uk
Australia
http://www.kidshelp.com.au
(0061) 1800 55 1800
New Zealand
http://www.kidsline.org.nz/About-Us_319.aspx
0800 54 37 54
http://www.whatsup.co.nz/teens
0800 942 8787
Ireland
https://www.childline.ie
1800 66 66 66
USA
Child-Help 1-800-422-4453
1-800-8255 (for talking) 1-800-7842-433 (for suicide)