Can’t get Back to Monstro in KH! Help!

Alright, this is royally pissing me off. I want to get all the 99 puppies, but I’m missing a few from Monstro. Everytime I try and go back to whale Goofy always says hes gone! Grrr. -_- So irritating. So does anyone know of a way to get back to Monstro? I’m at the final save point in the game and I want to see the hidden FMV.

Monstro will appear randomly between , just aboard your Gummi Ship, use the red portal located southeast of Olympus Coliseum. Once you’re in control of your ship, keep flying. (Be sure to go through the portal and don’t skip it) You’ll meet up with Monstro eventually or try to embark from Agrabah to the place where you meet Monstro for the first time.