I Had An Elevated D Dimer, And It Is Still

I had an elevated D Dimer, and it is still high. I am in good health and have gone through multiple scans and chest X-rays. I was admitted to the hospital as a precaution and injected with anti-coagulants and had dye injected for further investigation. Nothing was found. An ultra-sound of my legs followed and everything was clear. I was released and given a blood thinner to take for two weeks. The high D Dimer was almost the same after 8 days. The doctors are arguing with three saying that I can return to full duty and gym with the other group saying more investigation is needed. This has been the most confusing experience. I do not, if I am good and should be worry free or what exactly am I supposed to do.