Do you have a fitball? Sitting on that and leaning onto the back of a chair may help. The rocking helps too. I found slow, deep breathing and rocking in rhythm helped a lot.

Here's one I read on spinning babies - get up on the couch on your hands and kness. Slowly and carefully lower you hands to the floor and lean on your forearms. This moves baby up towards your sternum and encourages them to rotate to anterior. You may need help getting out of this position. I slowly slid my knees down to the floor. Putting cushions on the floor to land on first helps

Do you have someone who can give you counter pressure on your back?