ASCUS means atypical squamous cells of undetermined significance. Since you don't have HPV, I'm going to move this to women's health, so you can see if anyone without HPV has had this happen.
I'm sorry it's happening - I'm sure it's very frustrating.
Here is from another website. "ASCUS is the most common abnormal finding in a Pap test. It may be a sign of certain types of HPV, but it may also be a sign of a benign growth, such as a cyst or polyp or, in menopausal women, of low hormone levels." It is not considered a sign of cancer. My guess is that since you are 54, if you are perimenopausal or menopausal, the likeliest reason is low hormone levels. Certainly stop worrying about HPV; you have been tested and it is not there.
As I read your post, I wondered about your age and menopausal status. Because, as Annie mentioned, ASCUS can be caused by low hormone levels. Some doctors have been known to Rx vaginal estrogen (cream or suppository) as a "test" to see if restoring vaginal and cervical estrogen levels resolves the abnormal results. And it oftentimes does. So if you feel you need to test this out, see about getting an Rx and using it for a short period of time before having another pap.
Many thanks for your contributions. Your help is very appreciated especially during moments like this :)