Ex Is With Someone Else and It’s just hurting me deep down

So pretty much I dated this person for few months and broke up and it’s been almost 1 year 5-6 months we broke up and it was messy she had feelings for ex and me too at the same time and after couple months she is now with someone else new for like 6 months I guess recently they broke up and she start talking to me in such a way like she wanted to with me but oh boy I was wrong when I asked her out she just rejected me with typical friends one speech

And now I am trying to not see her TikTok but she is been posting TikTok like about bf or recording sunset and stuff like that and it’s just making me feel like panic spike and unfortunately she is my co worker too so I do sometimes have to see her fortunately I haven’t saw her for like3 months or smth but you never know when I’m gonna see her and it’s just makes me nervous and upset overall that she is with someone and I just feel like it’s not even about feelings

I genuinely think I’m just attached her and don’t really have feelings and she always been like hot and cold or mixed signals behavior I just don’t know how I just end this whole thing in my mind