I'm a physical therapist and have a tough time fixing my own sacroiliac joint pain. Obviously without an eval it is hard to say what you have, but SI joint problems are common in pregnancy with the loose ligaments.
I've done chiro and some muscle energy exercises to work on it (i've had it with all 3 pregnancies) but things are just so unstable for me in pregnancy I don't really get lasting results. You can try seeing a chiro experienced in working with pregnant women or a physical therapist specializing in pregnancy issues.
The pelvis basically has a right and left half joined by ligaments, so if it is SI joint pain, the exercises that would work for one person won't necessarily work for another, because it depends on which half of the pelvis is rotated, and whether it rotated forward/backward. So without an eval, the exercises to "fix" it could make it worse, kwim?
I know how frustrating it is....I usually get it starting at about 14 weeks, even before I have a huge belly, just due to the relaxin hormone kicking in. I feel like there are so many things I'd *like* to be doing (walking, getting
things done) but it is so hard when I'm hobbling around. And then when I do overdo things (sometimes the pain isn't so bad in the moment for me...) I pay for it sooooo badly later that night.
We're in the homestretch. I hope you can find someone to work with if you are in that much pain