Sounds like baby pressing head down on cervix. It's been happening to me now for weeks and I'm still pregnant (due in a week). Doctor told me it's normal. Look up lightning crotch and see if it reminds you of your psin. Good luck!
My dr said just ligaments very stretched but def check with your dr!
I've had that where it feels like an ice pick stabbing me down there. It was pressure from the baby"s head pressing on nerves.
You should call the e.r and ask if you should come in.
Go to l&d to get checked out incase preterm labour good luck