Hi
This may be because of avoidant personality features.
Your introvert from childhood also matter a lot.
You have good insight about your problem.
Work out on your problematic area in positive way.
Next Steps
Meet the workmates and wish good morning as a start up.
Join them for coffee or tea. can try lunch too.
attend office related functions and party.
Health Tips
You can try CBT with relaxation techniques with psychologist too