Daughter wishes she was dead

Long story short. I had a message from the school explaining she struggled with her staffing today and was unsure as to why she did not want people she was with. Staff allowed her to do her work on her own and gave her space throughout the day. Towards the end of the day, she jumped the fence and ran away from school however came back on her own and was given a staff change. My daughter refused her crisis cards (communication pecs/cards). She hit out at staff and threw chairs when she got back to school and struggled getting into her taxi at the end of the day, (the school called me and put my daughter on the phone). 

My daughter broke down and was shouting all sorts, making no sense, crying wishing she was happy and that she was dead. She said the taxi is the biggest issue but she doesn't know why. I don't know why and staff don't know why. They've tried everything, schedules, timers, having preferred staff, just everything to get her to the taxi but it takes her nearly an hour to get in most days. I don't know what to do. I want her to be happy. Staff are going to give her some support tomorrow and see how she's doing after today. 

I'm sorry again for ranting on but my husband is no help and I get some amazing ideas from here which have honestly helped solve some issues. Thank you. X