Cat acting funny. Arched back + constant purring + tail sideways

Went on vacation for 10 days and left my cat under neighbours care. She was good for the most part but I noticed she did not eat much but she was using the restroom like regular.

We picked her up in the middle of the night and took her home and as soon as we did, her behaviour started to change. She began to constantly meow and arch her back as well as keep her tail down and to the side (not swaying). At first it looked funny and was but now I’m concerned as it’s been non stop for the past few days. I hardly think she’s slept because I haven’t. Even after distracting her with toys and treats she will continue to meow and see attention. Is it possible she just missed us a lot and is now vocalising that she’s happy? She is just 7 months old.