mempool too backlogged to get to my transactions?

So added a couple super low priority transactions few days ago. Thinking they'd get processed sooner or later no big deal whenever. Well, then this whole mempool being the largest it's ever been and yeah... pretty sure these things are not getting processed. I was under the impression they'd auto cancel after 72 hours but so far they haven't. Where can I find more info on what is going to happen? If I look at the transactions they still just say they're at the very end of the memory block but were added over 3 days ago.