Had some therapy for this about 8 years ago and turns out it was down to having a very disfunctuonal family as a kid (big arguments between my parents and grandparents and my parents splitting up for 3 years when I was 11), family being impoverished to the extent that I had to live with grandparents for a while, and a mother that has been reminding me that I’d be on the streets if I didn’t work hard at school from a very early age.
Packed it in shortly after all that came out.