Phantom Photos and Messages filling up iCloud storage

Recently, I filled up my 200GB iCloud storage and received an email letting me know. Since my photos took up the majority of my storage, I went through old Photos and downloaded some larger ones to move them to an extra hard drive. Afterwards I deleted them.

In total, I cleared out 7GB of photos, but my iCloud storage said I had cleared nearly 50GB of storage. How is this possible?

I recently received ANOTHER email from Apple letting me know my storage was full again! It turns out that I have somehow filled up my just-cleared 50GB of storage with Messages data in the past two weeks. Here is my storage breakdown now:

I have been using Messages just like I always have for the past 5 years, and have not recently exchanged any huge files with anyone. So I find this rather improbable, and would like to kindly request an explanation on the breakdown of this Messages and Photos data. It seems a bit inflated to me, especially since Messages will not tell me what exactly is taking up this storage.

Thanks,

Andy