Suggest Treatment For Sudden Pain And Numbness On Legs

Last night i was getting dressed when a pain suddenly shot down my leg. I teach a fitness class which i did just after feeling this pain and once i finished the pain got worse. my leg felt numb and when moving in bed last night it was waking me up. I have woke up today and it seems to have got worse. It now is in the lower back at both the centre and right side and hurts with the slightest bit of movement. Can you tell me what you think this is?