[willcannings]

You already have a lot of advice :) But I'll add that if you focus on negative memories a lot you may need to consider if you have OCD or an anxiety disorder, and the anhedonia could be a sign of depression. The best treatment for these disorders is a short term medication with longer term psychological treatment (normally cognitive behavioural therapy).

But, if a psychologist or psychiatrist is out of the question, you can try some cognitive behavioural therapy online for free and in private: <http://moodgym.anu.edu.au/welcome>; The study behind this website actually showed it was more effective than visiting a therapist in person! There's a decent number of CBT exercises to complete, and it seems quite a few people get better simply by using the site without any psychological intervention.

But more importantly: it's sometimes possible to channel your negative emotions to good use. But sometimes it's not, and that's OK. Forget the advice that you should just 'man up' - if you feel the need to reach out here then it's a sign that what you have may be more than just a low attitude. It's OK to ask for help, it's OK to get it, and regardless of whether there's a stigma attached to mental ill health, it's OK to get professional help. There's nothing 'wrong' with you, but you can get help for everything you've mentioned if you feel you need it.