it is not uncommon to have no period at all when you use the unvarying for a long time. this happens with pills as well very commonly.
however, I am not sure why you had the long periods as well. it could be that you were usng some sort of medication like an antibiotic that made the uncaring less effective at controlling your bleeding. or it could also be that it was just breakthrough bleeding
and that you might need a higher dose birth control to control it. I doubt that would be the reason since if has worked for you for so long.
there may also be a polyp or infection or inflammation of the cervix
that would explain the bleeding too. your doctor should be able to identify this on an exam.
in the meantime continue the Nuvaring
to protect from pregnancy
and see our doctor for an exam. hopefully, he/she can figure it out. I hope this helps, please let me know if you have any more questions.