Try drinking lots of water and lay down with your feet up. Change positions to your side, do that a few times. Try taking a warm shower. Lay back down and try drinking as much as you can, if you can tolerate some electrolytes, that would be great too. If you don’t have any relief from that, I would definitely call your doctor.
I had moderate to severe cramping for over 36 hours around week 24 and ended up going to the hospital just to be safe. After checking to make sure I wasn't at risk of pre-term labor, they said it might be that I was slightly dehydrated (and suggested adding electrolytes), but they couldn't determine what it is. Thankfully, the cramping went away after a few days and hasn't come back, but it gave me piece of mind to go to the hospital just in case. This is my first, so I'm not sure how Braxton-Hicks even feel, but mine also felt like intense period cramps.
I had severe cramping a couple weeks ago and it ended up being asymptomatic UTI. Maybe try checking for that.