Since I can't change my prescription, what can I do to improve my pregnancy vision problems? Blurriness and focus shift, no high bp

See eye doctor. Some patients experience a change in their prescription during pregnancy. If it is relatively stable and a change in glasses helps, then there is no reason you can not change your glasses. Some patients get dry eyeduring pregnancy which could be the cause of the blurred vision. If this is the case, using frequent artificial tears will help.
Check sugar. Blood sugar variations can frequently be the cause of the lens in the eye swelling and shrinking leading to focus/blurring issues. Have your doc check it!