I do not think that your old auto-saves are retrievable. Premiere over-writes version 1 after it has written 5, then 2 after 6, and so on at your settings. So if you save every 3 minutes with 5 versions you have only 15 minutes protection!
You need to set the max number of versions to a higher figure in Edit > Preferences > auto-save tab.. I auto-save every 10 minutes and keep 20 versions, and even then I have come to grief on one occasion.
Your auto-saves are in the "Adobe Premiere Pro auto-save" folder which will be located alongside your project file
The first issue is what happened to the original project? Don't gloss over what caused that issue, as it may happen again if left unresolved.
Second, make sure you're opening the autosave version with the newest Date Modified, not the highest version number.