Friend dating ex (an update)

Hello all. I had posted a while back about this issue on this sub and how deep I was in my misery. Thanks to everyone who commented and tried to help. I tried to apply and practice all the ideas and concepts that people mentioned but I have failed, again and again. I'm just tired and exhausted now. I'm on meds again combining it with therapy but nothing seems to work. I've lost all hope. The friend and ex have forgotten about me and how miserable I am. They are happy together and everyone is rooting for them. I feel alone and defeated. I continuosly have suicidal thoughts and it just seems so peaceful to let go of all this. I've only made mistakes all my life, always taken the wrong paths which has led me to nowhere and without any friends. I've never wronged anyone. No one gives a shit about my life which has convinced me that my life is meaningless. On top of that, my brain has convinced itself that I must live in the shadow of the their great love. I'm a side character in my own life. I've been suffering with physiological issues like palpitations and heart pain, and I don't know what to do. If you can, please help me. Thank you