Applying for pension on grounds of I'll health


I am new to this forum but would really appreciate any help or advice anyone could offer me. 

I was diagnosed with breast cancer and had my operation in June 2018. I had an 11cm grade 2  IDC plus DCIS and invasion of the lymph nodes. They done  a masectomy and all of my lymph nodes were removed. It was all on the right side and has left me with movement problems and numbness. This was followed by chemotherapy, then a break as I had to be recut open due to an infection, maggot treatment which totally freaked me out ( but which did do the job and removed the infection quickly) further chemo and radiotherapy. 

Since all of this I stated a new job in September 2019 and made them fully aware of everything that I had had done prior to employing me.  However, I still suffer with fatigue, pain  and problems with my right arm and have now been diagnosed with ptsd and anxiety. I take Tamoxifenn . In addition I have a heart condition and a two  blood conditions.  I have tried to make the new job work but I am to tired, in pain and with the ptsd I cannot cope with work. I have also experienced some nastiness from other staff.  I have applied for my pension on grounds of ill health and they organised an appointment with occupational health. This lasted about 20 mins and the lady said that as she had no access to GP or specialist reports that she could not really make an informed decision. I thought that work would ask for these reports but they seem to be happy to base their decision on this 20 min phonecall with the OH. They are also pressuring me into an HR meeting as I have been off sick since 3rd September 20. 

I am so stressed with everything and wonder  if anyone has experienced similar and could tell me of their outcome regarding the pension or HR meeting  or offer me any advice.

I am so sorry to go on but I don't know where to turn.

Thank you