I've been doing some quests for the yes man
and I started up on the ending quest.
The problem is I don't have any saves
outside the ending. Is there any mods
or glitches that will fix my problem?

what platform are you playing on

did they disappear because I don't quite understand what you're saying.

He accidentally started the final quest and wants to know if he can escape, you cant, without mods.

try loading an earlier save

Did you read the OP?
He doesnt have one.

While I sympathize with the predicament, I'll never understand how one can play a game like this, for hours on end, on only one save.
When you live/like to live dangerously, sometimes you have to live with the consequences.

So you completely ignored the big box that said "This is the final mission! If you start this you're [censored]! If you want to continue playing/take time to save, please do it now!"?

Also you should probably start periodically saving or just hitting F5 and quick saving, just in case of game crashes or if you make a decision & realise that you don't like the outcome you can always go back.

Very little sympathy. The box warns you that you're at the point of no return and yet you still saved over your only save.

1. You should have more than 1 save in games like this.
2. You should not have saved over your only one after that gigantic warning.

Take this as a lesson and don't repeat your mistakes. Most people play through more than once anyway as you're unlikely to see everything in one go around.