Very toxic work environment

I’ve been dealing with a very toxic work environment for a while I spoke to upper management and HR and even formally documented it but nothing has changed. And the issue is that upper management and HR are the ones causing the toxicity. Certain employees are receiving preferential treatment due to their personal relationships with upper management which is affecting my job since they constantly mess up and I have to fix their mess. They even lied which almost caused me to lose my job but thank god I had a proof to defend myself. I feel like it’s been me against the mafia. I’m very unhappy I stopped working out and I gained weight. I’ve been eating junk food. I just feel stuck. I have been bullied and disrespected and every time I bring it up they gaslight me for example one time the whole department went to lunch I was singled out and not invited they were gone for remainder of the day meaning everyone in the department literally worked half a day except me and when I brought it up their response “we didn’t invite you because we didn’t want to make you feel uncomfortable”

I am currently applying for other jobs but that’s going to take time to get a new opportunity. I’ve been forcing myself to work every day. Some days I called out because I just couldn’t deal with the backstabbing. I even stopped interacting with all co workers. I only greet them then go to my office put my headphones on and listen to music or audiobooks all day until it’s time to leave. This is not healthy

I’m so down and I just wanted to vent. Any advice or suggestions are truly appreciated I