Unless you somehow deactivated the "Autosave" function, you MUST have Autosaves or (Milestone saves) from before you entered the dungeon. It's simply not possible to arrive at such a location without the game making at least a couple.
EDIT: Oh, wait. What platform are you playing?
PS4
You may wander over into the main Bioware forums and look/post in the strategy and tactics forum and see if you can get help on how to fight them at lower un-optimal levels. I know all the green glowing quests do show a recommended level below them and ask are you sure before starting them...
There are people there who claim they can beat just about everything at incredibly low levels.
Have you looked into the load feature of the game, instead of the continue button?? It may have surprised you with an auto save...just something to ck.
It would help to know what mission you are trying to do, what level you are and who is in your party. I'm one of those that can beat things at lower than recommended levels in this game but, I need to know the details before I can tell you how to do it.
