has any single mother forgot important things from their child school

well im a single mother of two little ones, and today my daughter had a school field trip i totally forgot she needed to be at school earlier than her regular schedule and when we got there there was no one in her class and a lady from school staff said they had a field trip and they had left. Omg i felt like the worst mother ever how can i forget this, i been on my own for quite some time and have my hands full but omg i feel so horrible. I feel that i have so much in my mind that im forgetting whats important. Has any single moms had this happened to them..