Sorry that you've had sudden hearing loss. Sudden sensorineural hearing loss (SSNL ) is usually treated with steroids that must be administered as soon as possible after the loss is experienced. Did you receive treatment for it?

https://pmc.ncbi.nlm.nih.gov/articles/PMC3138949/ This article from the National Institutes of Health has a list of drugs that are ototoxic. I did not see doxycycline listed, but it may be there. If hearing loss is a part of your life it's always wise to ask about ototoxicity when receiving prescribed medication. Sometimes, due to the health issue, we have no choice but to be treated with ototoxic medications. It's important to know that some non prescriptive medications can be ototoxic to some people.

You've been told there's no connection to meds and your SSHL. Have you consulted an ENT specialist?