If you had folders/albums that you had manually created on your phone in your phone's gallery app, I'm not sure that will automatically translate to albums on Google photos. Also it is necessary to go into your Google photos app settings and be sure that the backup process is backing up all of your phones folders that you want it to.
I have an Android phone and in my gallery app on my phone, there are a few different things called albums. They reference the source of the picture such as gallery, screenshots, whatsapp. Google photos backs all of those up but doesn't necessarily automatically transfer them into separate Google photos albums the way that they were segregated on my phone, if that makes any sense.