Dropping and contractions at 30 was.

Mo • Soon to be mama of 2
For the last 3 hours I've been getting really uncomfortable contractions every 10 minutes or so. I also feel like he's sitting much lower (left) than he was a couple days ago. When do I call a doctor? I've also had to pee so so much more than usual, my back aches and I have a lot of discharge. He's been awfully quiet today though I feel him here and there.