Braxton Hicks vs contractions

I’m 23 weeks pregnant & I have really sharp lower back pain which then moves to my lower abdomen. It feels like menstrual cramps, my whole stomach tightens they last for a few minutes at a time. I’ve also had an increase in discharge and a few times I’ve had to change underwear throughout the day due to them being wet. I get these pains so often where it hurts to stand up & walk.