I'm sorry you're going through all this. It's hard to be in pain and be alone, especially at night.
I recommend that you do exactly what my daughter does: calls me anytime, day or night, when she is ill and/or frightened and needs some reassurance. She doesn't do it often, but she's still my baby and i'm sure your mom feels the same way. Yes, it's good to try to be strong, but if you just need a few minutes of reassurance, that's what family is for.
Like the poster above said, the first day is alway the worst (scariest). I hope you feel better soon! Also, take it a little easier and give your knee time to heal.