Cramps/shooting pain after rocking on birthing ball

Jordanna
So I'm nearly 37 weeks and bought a birthing ball for the whole 'gets baby in position' fad! Well I sat on it for about half hour this morning rocking more than anything a little bouncing but very lightly. Since then I've been having awful uncomfortable pain really low down like a shooting pain it makes me want to lean forward almost to relieve it! Anybody else have this??