Third Baby, New Symptoms - glute and groin cramps?

I am 37+5 with my third baby.

I had lots of real contractions over the last 24 hours but nothing patterned or growing in intensity.

HOWEVER, I feel a huge amount of pressure down onto my cervix and I can hardly stand or walk due to debilitating Charley-horse style cramps in my glutes and groin muscles. Like 100 times worse than my normal lightning crotch stuff. Completely new symptom for me!

Anyone had cramps like this? Is it just bad luck, or is labor near? Possibly just an electrolyte deficiency?