I had this with my last pregnancy and ended up in hospital and brace and crutches.
It never really went away after bub was born although it was better than it had been.
This time it arrived earlier and luckily the midwife/dr sent me to the physio early, after over an hour with him, he seem to think it started after a fall I had in my last pregnancy that the drs didnt follow up as bub was fine. So this time at 19 weeks I am already in a tube thing from bottom of belly to bottom of breasts, a brace and crutches with the advice to get a c section so I dont damage my pelvis anymore. As its really quite unstable and out of alignment by a lot.
Physio said 12 weeks after bub is born we try and start to make it better. Im hoping he can do something, its so painful and sex is just a no go