Agonizing constipation

Extreme constipation I'm a 18 year old female college student. 140lbs 5'10 I take ritalin 10mg twice daily. I don't have any other health issues and I usually drink at least 2 liters of water a day. I’m currently experiencing the worst constipation I’ve ever felt in my entire life. I haven’t used pooped in like 5 days. Yesterday, when I first felt the urge to poop in that time period I couldn’t pass anything. It was all in my rectum, and it was too big/hard to pass because whenever I would try the hole would hurt a lot and it felt too big/hard/solid to. This morning I stayed in the dorms for all of my classes because of how bad it got. I bought a saline enema and a bottle of magnesium citrate. I just took the magnesium citrate 50 minutes ago, and I took the saline enema then too. I held it in for a full 15 minutes but when I was done nothing came out. Right now, there’s an extreme pressure on my rectum, like somethings in there and can’t come out. There’s a dull pain that I’m feeling every second. Whenever I try to use the restroom I just get overflow diarrhea and my stool stays hard and can’t come out. I can literally feel it whenever I walk, sit, and as I’m laying down in bed.