Wow, not fun.
Many things can be going on. My first thought is that you are 80, and it takes a little bit longer to heal thru some of these viruses than it would have for you at a younger age--I think it just comes with age. I also find that even for me, some of these viruses that we occasionally become bothered by, take a long time for us to get over. We usually think the proverbial 7-10 days, but it ends up being 3-4 weeks--so for me, you may fall in the range of this.

The hoarse voice and the "virus" together can both be directly or indirectly related to post nasal allergic or non-allergic drip, and/or reflux from the tummy which can also be aggravated or perpetuated by the post nasal drip.

You do not have to run into the doc right away. You can do some nasal washes with saline to help bath the tissues and clear out the post nasal drip, and use a little claritin to see if this helps dry up the drip, which which help with the hoarse voice (vocal cord irritation) and the reflux; You can do this for a week or two and try a little bit of a bland diet so as to not aggravate the tummy right now, and you can see what happens. After another three weeks, I imagine you should be fully over the "virus"--and the tissues should be healed; you can try the melatonin, this should be OK; and remember, the dryness of your mouth is a natural phenomenon as you age--lemon drops help you to keep salivating. Good luck!

Miriam Ragab