mild sharp pains in uterus?

Sam
Has anyone else had mild sharp pains in their middle lower abdomen? They have been coming and going periodically for a couple of hours. Mainly when I get up to pee, they start after I get back to bed and fade after about 20 mins. Braxton Hicks? Ligament pain? 
It's the middle of the night so don't wanna have to go to hospital but am worried! No blood so that's good.