Am I Overreacting? Thoughts?

Ha

So I had been very in love with this guy. He dumped me on Halloween. Some background on him. A family member of his died and the two year anniversary of their death is coming up. He was very depressed last year and in a bad place but he cut everyone out of his life and got to a better place. When he dumped me, he said he felt himself going back to that dark place and that he couldn’t be with me right now. I told him that I understood and that I wanted him to get to a better place and to do what he had to. I was of course devastated but didn’t want him to know that. I gave him all of his stuff back and when I left the next morning, he had left my favorite shirt in front of my door, on purpose. That was confusing. He also has gone out to concerts and parties almost every day, but that’s who he was when we were dating too. He has been hanging out with my friend (they knew each other first and that’s how we met) and she took him to a football game yesterday. They posted pics together and I was sad but happy he looked like he was doing better. But in one of the pics there was a blonde holding his neck and on him. So I got jealous and looked her up. He had liked every picture she had posted since him and I started dating. I should mention that every photo she posts is very provocative with her ass and boobs out. I had a bit of a meltdown and cried my eyes out. Every guy I have been with has cheated on me so that just made sense. My friends tried to tell me that maybe they were also just friends and he is just getting out to feel better. I feel like it is too much of a coincidence, but idk if I’m just being the jealous ex girlfriend. Thoughts?