Harassment or Discrimination at work

Yesterday I had a meeting in which my manager called me ‘unapproachable’ and said that I ‘should smile more’.

My job is not customer facing and I work primarily on a computer with little to no need to collaborate with colleagues as a part of my job.

I have already told my manager that I’m Autistic, and I also suffer with PMDD. They are well aware that this can make it difficult for me to communicate with others.

I have applied for reasonable adjustments but they are digging their heels in at every corner.

I’m not really sure what I can do, but I feel like this is harassment or discrimination? And I don’t feel that calling me unapproachable is very appropriate? Any advice? Should I take it further?