Hello Boogiethepartipoodle,
I understand you're missing some of the songs that are supposed to come with the pre-ordered album you purchased. I'd want to figure out how to get all of the songs I paid for if I were in the same situation, so I can definitely see why you would reach out for help. I'm happy to assist you with this.
First, I recommend taking a look at the guidance on this issue listed in Pre-order apps, movies, music, and books, specifically this section:
When your pre-ordered item becomes available, the payment method that you have on file is billed, and you receive an email that says your item is ready to download. If you turned on automatic downloads, the item automatically downloads to the device that you used to buy it.
If you don't see a pre-ordered item that you expect to see, find the item in your purchases and download it. If the item is an app or game, you can also find the item in the App Store and tap or click Get."
If you're not seeing those songs available for redownload, take a look at the steps in the "If you don't see the item that you want to redownload" section of the "Redownload apps, music, movies, TV shows, and books" support article linked above. If you need continued help with this after following all of the steps, I recommend reaching out to Apple Support: Contact Apple for support and services.
Thanks for using Apple Support Communities.
Take care!