I'm glad things have improved for you! Now, don't push yourself, missy! Take it slow and don't over do it.
I think the rule of thumb, for old threads, is if you have something to contribute (updates, pertinent info for the thread) to the thread it is okay. If it's just a comment to say how funny the thread is, how dumb someone is, or make other non contributory comments, it is frowned upon. If you have a question, maybe reaching out to admin/mods is the best answer.
I'm a pill hoarder as well. Sometimes, local communities have a 'pill day' where you can take old prescriptions to dispose of. You might also ask your local pharmacy. Just don't flush them down the toilet. That's a good way for prescription medicine to end up in the water supply.