38 weeks constant intense lower back pain

Can anyone tell me if this is normal or if I should call the birthing center? For the past week I've been having regular Braxton hicks that start in my back and wrap around the front of my abdomen and into my thighs. They're anywhere from 10-17 minutes apart and last about a minute long, but if I move around they ease up. I used to just get the back pain when these happened, but since last night it's been constant. I'm to the point of tears from the pain in my lower back and can't make it go away no matter how I sit. My son also hasn't been moving regularly for the past few days. I feel him move maybe three times a day. I've also been leaking watery discharge (for a week now but I think it might just be pee because it's yellow tinged with (chunks?) in it and I mentioned it to my doctor this week and she didn't seem concerned and said it's probably the baby pushing on my bladder and me leaking. Pink little chunks about the size of rice but there's only a few. I'm just not sure whether to call my birthing center today or wait for my appointment in 4 days to bring it up to my doctor. I'm 38.3 weeks