Is this separation anxiety or FOMO? How do you tell the actual difference, because they seem the same to me.

I puppy sat today and this is an almost 2 year old dog. She does have separation anxiety but I was told it was mild and being worked on. There was never really a time where I just left her alone for a long time, and I did frequent 1:1‘s with all the dogs as best as I could.

1. She peed and pooped in the house, specifically the room she was in.

2. She corrected my puppy once, no nipping just a squee and during a time I did a “test” to see what she was doing after she did this he sat in a corner and she pawed and cried very loudly at the baby gate for 5 minutes (I kept them separate after this). Thankfully he started napping. I watched from the window.

3. She attempted to destroy one of my kennels.

4. She attempted to destroy a rug I have that is outside the baby gate(idk how tf she pulled it through).

5. She banged against the gate a few times with her front paws

6. I heard her screaming from outside the house during potty breaks with my puppy and older dog.

These behaviors only stopped when I was present. I went to my room to change into my jammies and she went nuts. I come back and she is sweet as can be. I feel like the last time she was here, she maybe did a couple a whines when alone but then again someone was always somewhere in the house. I had chores to do today where I could not devote all my waking time to her, and my puppy and older dog are always fine when I have to do things alone so long as they can see each other. My friend said this is more FOMO than anxiety and that she never does this at their house, but just last month she told me about a incident where the dog was alone and she tore up papers on her kitchen table.