Unfortunately, everything you didn't tag or rate is gone :(
There was a server crash back in late January and in simple terms, what connected a person's marking for a manga to their account got corrupted. They tried to recover the data over a few weeks, and a decent amount of people (myself included) got a lot of their stuff back. Stuff that was tagged/rated was easier to recover since there still was a way to connect the "mark" status to the account. But stuff that was not tagged/rated was way more wishy-washy. They've finished their passes, but many people's lists were completely unable to be recovered. Since your stuff isn't back yet, it most likely never will be. As sad as it is, I recommend you start rebuilding your lists.
Check your "history" and "bookmarks" tags on here to see if you still have data there. That along with searching your browser history can be a good place to start :)
Also, as for the one you don't remember the title of, if you make a new question where you describe it, I'm sure somebody out there has an idea :)
is there any way to get back my reading and to read list i’ve been a bit inactive cause i haven’t had the time to read and everything is gooooone. and i had so many good ones saved and currently reading. there’s one in particular i was rly invested in but don’t remember the tiiiitleeee