Just start over.

You need to prepare for the boss fights. Listen to Hugin the crow who tells you hints. He even tells you to get your best gear before you fight when you arrive at the shrine.

Things he tells you are very important and should be read... trust me, you need to read that stuff.

Hitting tab will bring up a menu you can select him and get all the things he has said listed to read... but yeah I think your best option is to just start over with that knowledge.

Good luck, enjoy the journey.