What help can a GP provide?

Hi, I’m in the UK. I’ve had fibromyalgia for a few years now, only officially diagnosed a few months ago after what felt like a battle which I won’t go into. I’ve currently in a bad flare up and it’s impacting my ability to work, my manager has suggested I go back to my GP but I don’t know what they can do? I already take paracetamol and ibuprofen and 20mg amitriptyline per day. Is there any other medication that can help? I’m really struggling!