I don’t know what to do, I’m worried about my ex finding out.

So my ex and I of 15 months just broke up. I broke up with him, I was just unhappy and we had some previous problems for quite awhile. There’s this other guy tho who is super cute and is friends with my friend. We’ve talked in class a few times when we sat by each other previously but don’t talk since we don’t sit by each other anymore. I have him on Instagram but not on snapchat which I would like to have him on and I could just ask my friend but I’m nervous abt the word getting out that I think he’s cute cause I told my ex I just want time to focus on me. The cute guy tho posted on Instagram a pic of a sunset and just captioned “I smile more now that you’re around😍” idk if it was just a caption or if it was about someone specific or not. But it makes me lowkey bummed out because I know it’s not about me and I wish I could talk to him but I’m worried abt the drama that would go on at school if my ex found out since he still has feelings.😢 opinions please! We are 17 btw.