Had a positive pregnancy test followed by many negative at dr office, they refused an ultrasound. paid for ultrasound at outside facility and gestational sac and yolk sac seen but couldnt see further with abdominal. is it possible this is viable?

A viable system creates the chemicals that turn a pregnancy test positive. When the system dies, so does the chemical production. If you now have a true negative test, it is not viable. Some cite as many as 1/3 of conceptions shed for various reasons. Early loss can mean the material did not have the proper genetic composition to continue.

If your HCG level in blood has dropped, the circumstance you described is not suggestive of a viable pregnancy. About 25% of early pregnancies are lost spontaneously, usually due to chromosomal defects in the embryo. Wish you good health!