Suspicious of my boyfriend:(

I need advice.

My boyfriend (18) has gone on a family holiday in turkey for 10 days. For the past 2 days he’s been acting weird, for example i bluntly said goodnight to him early night and he just said goodnight i love you too. The next day i told him i wasn’t feeling great so i probably won’t be responding and he said ‘I hope you feel better’ without even asking what’s been going on.

Later that day I come to find he followed this girl on instagram that he’s met on holiday & i confronted him about everything. He said he’s been busy and he met this girl through two other confident guys at the hotel that he also made friends with. The girl also knows my boyfriends friend too (what a coincidence)

HOWEVER, I just looked and the girl and my boyfriend unfollowed each other on instagram after I had mentioned her to him. Is that a red flag? Am i overthinking it? Why did they unfollow each other? I don’t want to accuse him of anything but to me it’s all suspicious. He’s been drinking, going clubs etc, idk.