Devastated

My mum died just last night. She has had back pain for years having osteoporosis, but the day after Boxing Day 2020 she said she had excruciating back pain, she also had a large lump near her spine that she kept quiet about. I called the gp and he visited her at home. He referred her to the oncologist and she had scans and biopsy on the lump. She was diagnosed 15/01/21 with CUP, Cancer unknown primary. I moved in to care for her, and she soon lost the ability to hold herself upright. We were told it had gone into her spine, which had fractured due to the cancer. It was also in her ribs. Last Saturday she said she needed to stay in bed as the pain was so bad. I called district nurse and she gave mum pain relief and sedation through a syringe drive, as she had to lie flat so couldn't take oral pain medication. That was it. She stayed pretty much unconscious for 5 days, but still struggled with pain. She passed away at home with me, my step dad and brother with her last night. I am utterly devastated, in shock, it was so quick we didn't have time to prepare or understand. We didn't get a month with her after the diagnosis and I don't know what to do.