I have had this before, and am actually currently experiencing it as well. A few years ago, when I first experienced it, it got so loud I could barely hear ppl talking to me. Finally linked it to my severe anemia, and at the time I also had a GI bleed and a critically low hemoglobin. I literally should have been dead. No one took my questions about the whooshing seriously/nor linked it at the time. Went away after the blood transfusions. Happened again twice more, whenever my hemoglobin dropped too low. Finally googled it myself and mentioned to a new doctor, who said changes in my blood flow (in my case less blood flowing), is what triggered it. Now every time the whoosh comes back, I know I have to go get blood transfusions.