Hello Friend, Good that you are seeking a help. Yes, too much thinking about any past bad experience will put you in depression. If you block your mind and time only on one topic, you tend to ignore and miss good things around you and feel bad about it later, which aggravated your depression and you express that with anger, Mood swing and sometime discomfort at body functioning as well. You unnecessarily think that there is wall around you and you are  into isolation,which is not true. So, the solution is get ride of this past thinking. Focus or divert your mind are enjoyable things like hobbies, music, arts, career, vacations, friends and families. If you need help, reach out to any psychology counselor locally or reach me online through Practo app.

Hi dear the way ur expressing u might have some symptoms of depression it's better u consult any psychiatrist personally in ur city ASAP and get ur evaluation done properly it's for ur own good and wellbeing tc. Dr Ankit Patel Psychiatrist  Pune .