7weeks postpartum heavy cramping

Help! I need answers 😭. So today I held my urine for a long time because I was in a dreadful long line and I had my baby in a baby sling . I could feel the pressure of her weight on my bladder but I couldn’t really do much about it. After two hours I finally used the ladies and I had this cramping that started of mild but became excruciating painful 😖 and I had like a little mucousy discharge 🤦🏿‍♀️ I took painkillers and it went away. Has anyone experienced it before ?