So, I am really worried. I inserted a dildo in my ass. It was about 9' long and the girth was like 3'. I played with it for 15 or so minutes. The following days after this incident have been really painful. My lower backbone hurts, I can feel that the hip cheeks have loosened/opened up which is so depressing because I used to be tight af. This situation is really taking a toll on my physical and mental health. I urge you to please tell me a solution.
I am too embarrassed to see one. That is why I turned to online health forums
You're to embarrassed to see a doctor yet ask on a student forum?!
I'd have problems if I inserted a nine foot dildo that was three feet across too...
See a doctor. You probably won't be the first person with something anal related that day and they'll be glad you haven't ended up with something stuck inside you.
Go to your local GUM clinic. Then you don't need to see your GP.
There's no such thing as GUM clinic here
Sexual Health clinic then.