What Causes Difficulty In Movement Post Practicing Stretching Exercises?

Help, I have been practicing and stretching to do the splits with my friend and she has been training me. I finally got it so we were in cheer practice and me and her went down at the end of the dance, and we kept going over that part, and all of a sudden. I couldn't get up and she had to help me, I could barely go up the stairs am I streched a lot before this, and now when I go down its like my hip rotated and it's like inpossible to go down.