There are a number of organisations, forums, and groups that provide help and support to people with mental health problems. I have tried to list some of the support available on this page. Note, many of these will only be available to people living in the United Kingdom.
If you feel in crisis, there are several options available, which have been summarised on this webpage (from mental health charity Sane).
General emotional support:
Sane Mental Health Helpline (0845 767 8000, lines open 6pm-11pm, all year around)
Samaritans (08457 90 90 90 , lines open 24 hours per day, all year around)
Mind Infoline (0300 123 3393, lines open Monday-Friday, 9am-6pm, or email email@example.com)
Rethink Mental Illness Advice Service (0300 5000 927 lines open Monday-Friday, 10am-2pm)
Mind Legal Advice Service (0300 466 6463, lines open Monday-Friday, 9am-6pm, or email firstname.lastname@example.org)
Forums to talk to other people with mental health problems (online)
Elefriends (operated by Mind)
Black Dog Tribe (operated by Sane)
Friends in Need (operated by Depression Alliance)
Rethink Talk (operated by Rethink Mental Illness)
Peer-support groups to talk to other people with mental health problems (offline)
Click here for a list of peer-support groups (collated by mental health charity Mind)