First Mystery Dungeon game. Did I screw myself over at Mt. Blaze?

Going through the story so I only have my partner and myself. We’re around level 21. Got to the top of Mt. Blaze but Moltres insta-wrecked me. Now I have no healing items, no elixirs, no additional partners, and no access to shops. I can’t even get back to the boss now, nonetheless get there with healing items and actually beat Moltres.

So is there something I missed? Should I have been grinding more earlier on in the game? Is my only choice to just keep going through the dungeon and dying over and over again so I can level up?

I’m getting almost no berries or apples in Mt. Blaze and I just feels like I’m stuck between a rock and a hard place and am quickly losing the motivation to play the rest of the game.