If you are seeking immediate help you can contact The Samaritans.
If you are in need of urgent medical assistance you can attend your local Accident & Emergency hospital or ask for an Emergency GP appointment. You can also call the NHS advice line on telephone 111.
Local NHS mental health crisis teams can also be contacted for emergency situations. For Waltham Forest, Redbridge, Barking and Dagenham and Havering there is the North East London Foundation Trust (NELFT).
For individuals seeking free/low cost therapy there are organisations which provide this, usually in a short-term manner. Here are some organisations listed which are local to East London.
Self-help resources can be extremely beneficial to some people. Mind provide a lot of information for example regarding anxiety and panic-attacks. There are also websites which provide information to assist people for example with sleeping difficulties. I have listed a few resources below.
There are also many books, local charities, self-help / support groups, and provisions such as eco-therapy schemes in different localities. Individuals may find these types of resources to be of great value in their journey towards greater emotional wellbeing and life satisfaction.
PCCS books is a good resource for person-centred literature.