Hi emz,
There is a condition that some pregnant women endure called 'symphysis Pubis Dysfunction". It is very painful and sounds a lot like what you describe. Mention it to your doctor and ask for a referral to a physio. A physio can give you some exercises and sometimes a 'belt' that helps to support the area. I feel for you as it is very painful. Try to make sure you get off chairs, beds out of the car etc with your knees together...
I hope you can get some relief.
Love Deb