It has been almost a year since the end of a 6 month relationship. I am ready to let go of my ex. However I have reacted unhealthily to the breakup since then till now.

When we broke up I messaged him and cried for 2 months telling him I missed him. My work friendships and quality declined heavily because I thought about him all day and could not stop. 

I went NC for a month when he didn't reply to my messages. Then messaged him because I wanted his contact. He continued to communicate with me and I wanted to see him one more time to get myself closure. He kept denying, lying he was working late and making time with other girls. I got jealous even though I was trying to be friends with him.

I finally realized he was just a liar and that the relationship was built on lies. I went to his house and keyed his and destroyed his air mattress out of rage. I told him out of fear and because he lied about cameras.

I then messaged his new girlfriend that he would lie and cheat on her as he did me. They both blocked me.

Periodically, I watched her public stories and was slowly getting better at letting time pass without watching them.

I realized what a terrible person he was to me and I deserve better.

I googled his name one day because I decided I should move on, and to see if he was hiding anymore lies to me because he added me on a false facebook account when we were together. 

He got married to someone who wasn't his girlfriend and I know they were still together. 

I took to reddit to share this, but that was a wrong move because I guess his girlfriend has an account (which I figured from watching her story) and figured out it was me. I deleted the post because I decided "this is ridiculous, I'm done with negativity". This confirmed to her that I continue to watch her stories. 

 This only led to her further shading me on her story and subtle messages at me saying she's the new lover. 
I don't even care about him anymore, I just feel stupid I believed all his lies. 

Today is the last day I checked her story and she posted something alluding to her being with him.

They both know I'm psycho and haven't let go. But I am now. I'm stopping checking social media. I'm heavily embarrassed for looking weak to them and that I may meet someone they know.

What concerns me is all my behavior up to this point. I'm a different person from when I met him and have degraded.

I don't know if I am mentally stable right now. All I have been doing is ruminating on how I deleted the post.
I'm trying to distract myself and move on.

Is there a point of return for me?

Tl;dr: did VERY psycho ex things and fixated on a breakup of a short relationship. Am I mentally stable?