Is This Medical Negligence? Four Years of Misdiagnosis and Pain

I was first diagnosed with chondromalacia patella four years ago despite not having had any scans, blood tests or investigative operations (as is standard practice for this diagnosis). I received a course of physio at the time, which didn't help. I gave up for a bit and returned to my doctor about a year ago to discuss other treatments where I was told the diagnosis ans my physio had not been put on my notes so I would have to go through the whole process again. I have just completed 6 months of physio and my pain is spreading and getting worse. I recently asked for a letter from my doctor detailing the condition as a disability and its status as a disability for accommodation requests at uni and was told it wasn't possible as none of my diagnoses or courses of physio were recorded. I now have to do it all again and may risk not getting suitable accommodation at uni. my pain is becoming more and more unbearable and I have been told it is 'all in my head' despite being often stuck using crutches to get around or missing out on activities because I can't walk. I'm sure this couldve been avoided if everything had been done properly I the first place, four years ago. is this medical negligence?