This will sound immature but I’m having trouble moving on.

Some background. Was in a long term relationship and after a year of healing I decided to try dating again.
Met this guy who was only staying in the country for three months. Decided to have a casual relationship with him. Throughout he was hot and cold, ignore texts for hours, only see each other on his terms etc
I thought it was his way of keeping the relationship at his pace.
but when we were together we had fun.
I did catch feelings for him even though he told me not too as he would be leaving soon.
He then went back to his country. He was messaging me more saying he was thinking of me etc
Then I noticed he removed me from Facebook and Instagram . That did upset me, his profiles are public so I can still see them if I wanted to.

He also started blocking and unblocking me on WhatsApp every other week. I’ve ignored it and not risen to it.
He is in his 30’s by the way.
I know I need to move on but these games are driving me mad. I wanted to just have that contact open but he makes me so anxious doing this.
I’m also not sure if he is back with his ex girlfriend as he posted a photo she took of him the other day.
Why is it so hard for me to move on and not think about him all the time