how to move on?

I've been friends with this guy for about 3 years now and whilst i was initially worried about us losing contact over the summer, i now feel differently. We've both remained good friends and still talk to eachother when we have free periods. Recently, i've noticed a few signs that he and another acquaintance/friend may be dating. For a bit of context, this girl used to tease us all the time and say that we were dating or had something going back in high school which im now realising mightve been her way of telling us that shes interested in him. He doesnt really let people aside from like 2 peopke follow his insta but now ive seen her pop up as one of his followers. I also saw that they were playing games for a few hours together on discord and i've noticed that theyve both been online for hours at the same time. i never thought i liked him and i still dont think i like him because i dont present those in love "symptoms" but the thought of them being together bothers me and in a way makes me sad. I need to find a way to rid myself of these feelings otherwise it could all go wrong.
please help me