Why was he so angry

OK so 4 years ago, I saw this guy at this family event. He was a family friend and we shared this instant bond. I'm not gonna get too much into it but he would literally look out and try and find me in the room. Our eye contact would last for ages every time but we never got to talk because the second event was male and females serperate so we only in the same Tom for about five minutes.

Fast foreword last year:
Now my friend owns a meme account that myself and two others had the passcode to. I've been on it plenty of times and didn't know they followed one another until I saw a selfie of him while I was logged on. I wasn't sure at first but when I looked on his account at more pictures I knew that was definitely him. I could see he had a gf from the comments under his pictures. Anyway I continue stalking hair account for about a week or two before blocking and unblocking him so he's no longer following the account.

The reason why I did this was because there are funny screenshots of texts my friend has on there with my name on so when I realised that he would be seeing all these I wasn't too happy. (It was only my first name but I have a very unique name and it's an account that's very close to people in our town). I also told my friend who he was and asked her how long he was on there but she didn't know as he was a random follow (they don't know one another).

Now my friend and I were in town shopping, and I'm telling her something and when I look up I see some guy staring directly in my soul (what it felt like) kind of looking annoyed. He was kind of glaring at me. I've put on so much weight since I last saw him, so I don't know if he was just a bit taken back by me not being as attractive and thinking 'Ew I actually use to like you'. Or what. I never actually noticed him at first like my eyes just brushed past him and then i was slightly alarmed by the glare. When I looked back he was looking at my friend and then when I looked again he looked to the side It seemed as if he was pretty pissed off.

I told my friend that that guy was him and she said to me 'He was looking at you! I saw him and was thinking why is this guy looking at Emily?'

Later that day my friend told me she had sent another follow request and he declined it. Now I still don't understand why he was so angry. It's clear he thinks I was stalking him with my friends meme account because he saw her before looking away angrily. And he most likely saw my name in the screenshots. Or could it have been a combination of the fact that he thinks I'm stalking him and that I've gone fat?

His girlfriend also changed her profile picture to an old picture of him and her so he's definitely told her.