I don’t know how to feel

So my ex an I broke up like 5 months ago and ever since we text each other just to ask simple stuff like “how are we” and that’s been all two weeks ago he said he wanted to see me, we made plans and he just never arrived to the place.... now i know he has a girlfriend, that’s part of why we broke up. I thought he wasn’t with her because the way he texted me made me feel like he was alone. After this I didn’t talk to him I was mad and o don’t check social media, not a fan but just today I get into instagram and saw him with his girlfriend and I am feeling sad, I just want to run and cry, I know I shouldn’t but my heart hurts so much right now... I have anxiety and I don’t know what to do.😖