Why have my photos disappeared?

I don't suppose anyone here is an expert on phone photography? I'm certainly not.

For a fair while, ive been using the Adobe Lightroom app for taking photos with my iPhone 7. I prefer the Lightroom app over the phone’s default camera app because you can manually set the white balance. Handy when shooting under artificial lighting indoors.

Usually, photos taken with the Lightroom app end up in a library within that app. However, yesterday, the interface of this app looked a bit different than usual when I opened it up. And I was asked to sign in. Ive never had to do that before with this app. I do have an Adobe account (which I normally use on my pc) and I used that to sign in on the app. I took a bunch of photos with this app afterwards but when I got home, they were nowhere to be seen.

The Lightroom library shows the previous photos that were taken (over the last several weeks and months.) But there is no sign of yesterday's photos (that were taken after I signed in.) I also looked in the phone's default photo library but they're not there either. It's like the photos have vanished without a trace.

There appear to be three albums in the iPhone’s default photo library – Recent, Favourites and Lightroom. I have looked in all of them and yesterday's photos are not in any of them.

I admit that I was a bit desperate looking in the default photo library. I had a feeling that they weren't going to be in there. When I use the Lightroom app to take photos, the images first appear in the Lightroom library. I have to select each individual image in the Lightroom library and send it to the default photo library.

Ive also recently noticed that the photos in the Lightroom library have been organised into albums (but not by me.) And coincidentally, the names of these albums are the same as the albums in the default photo library. I did not set up those albums either. 

I don't know why there are all these changes to the Lightroom app (including having to sign in.)

The other thing is I can't even find the camera icon in the Lightroom app anymore. So I can't currently take photos with that app.

I don’t suppose the missing photos could be in the cloud? I found out that cloud storage with the Adobe Lightroom app comes with a paid subscription (which I do not have.) And just now, I discovered that you can get cloud storage with a tree trial. I have no idea if I have a free trial or not. I admit I was puzzled that I had to sign into the app the other day in order to access it. I never had to do that previously. And Ive never had to pay for anything to do with this app. By signing in, I don't know if Ive been put on a free trial. I originally found out about this app from a youtube video. According to the video, Adobe Lightroom could be used as a free camera app on a phone.