You should still be safe. Create such a M3U file (there's a big enough amount of tutorials on the internet) which refers to all discs of the game you want.Thanks for explaining that, first I've heard of an "M3U" file. Would have been nice to know before reaching the end of disc 1 ;P
Look for your save file as I wrote before and rename it to match your M3U's name.
I'm not sure what the extension of a PSX save is but presuming it's .sav your files should have those names:
FF VII disc1.bin/cue/iso
FF VII disc2.bin/cue/iso
FF VII.m3u <- containing entries for both discs
FF VII.sav
This might help you as well:
https://www.reddit.com/r/miniSNESmo...de_how_to_convert_psx_multiple_discs_game_in/