you can train specifically as something like a IAPT worker, do a clinical psychology doctorate, counselling masters etc
find a level of course which works for you and look at what they require, you can usually do a conversion rather than a whole new degree
to do anything within a psychology field you have to have a decent amount of relevant work experience so think about that too
You do your work experience as you learn because you can't volunteer as a counsellor until you are on a relevant course.
You can do very serious damage to someone without proper training.
Becoming a chartered/registered Psychologist involves a Psychology degree (in your case, a conversion masters), some work experience and then a doctorate (i.e. DClinPsy) - some, like Forensic, require a specific masters also.
IAPT (Improving Access to Psychological Therapies) train and hire Psychology Wellbeing Practitioners (PWP) who are CBT therapists that deliver structured interventions for a range of anxiety and mood difficulties. You can progress from there to be a high intensity therapist with full CBT accreditation
You can become a CBT therapist in its own right (and possibly some other therapies). From here you can work in a private capacity, or there are some jobs out there that look for CBT trained therapists specifically. You can also do 'lower level' jobs and use these qualifications to give you a significant edge in applying and progressing.
Then there are a range of therapist jobs, I'm not even sure what is out there career wise. ~Tara~ may be able to fill you in on this better. My guess is this ranges from specific modalities of therapy/counselling (i.e. marriage) to school counselling services or general intervention work, such as with a Youth Offending Service or family service.
Once you know where your interests lie, you can then pick the appropriate education/training pathway.