I just bent over and got a sudden sharp pain in my lower spine, could now not stand back up straight. laying or standing still fine, moving hurting

Probably fine...: If you didn't get any numbness or tingling in the lower extremities you're probably ok. Either pulled a tight muscle and created spasms or tore a ligament in the spine. Sounds bad but it is usually something benign, a partial tear that heals perfectly fine on its own. Warm compresses. Gentle massage. Give it 1-3 days. Make sure to try to keep it moving.