Afraid and Anxious : i went threw an...

i went threw an mental harassment at my job 5 months ago. Things they would do Made my social anxiety extremely worst. i worked in grocery store but in deli department. Thinks they was like when i was in mist of working on a task or customers they all be quiet and watch me. Nobody would talk to me and whenever i go off to the back or somewhere they have employee come and check on me. when i my back was turned very one would just be watching me they stop there own task even coworkers out on sale floor whoever was around. made me feel uncomfortable. i worked there three years this and i was told i was Great worker . i knew i was cause i appreciated having job and i cared to have it so worked hard and stayed focus and was never a problem. this was shock to me being treated this way after three years being there. made me feel like was i ever a good employee or was i full of myself. Why would they do that to me? What hurt the most was my closes friends even turned on me and stopped talking to me. i couldn't go to anyone cause they would lie and store manager was involved and so was all supervisors and all coworkers. When i would go to office no one would answer the door. and office is right there in front where the cash registers where so everyone was watching me being humiliated. and i would have have panic attack in my head trying to be noticed. and would also become very angry towards them. they did this on purpose so i cant have any witnesses. Cause if i were to go to HR they would just lie and plus who they gonna believe me or entire store?

kinda person i am is Very calm and quiet , and i like to keep to myself.

during the time i remain calm and didnt react to it either.

But lately have gotten little over my social anxiety . but im getting anxious about wanted to look for other job right now it freaks me out. cause in my head i think i was good worker . but now i feel like maybe i was full of myself thinking was good worker and i wasn't the whole time . Cause the same store manager told me couples times i was really good worker. cause eventually i made to Assistant manager for my deli manager. i would run the place and give orders. they i worked was that i would do my work to perfectly and stayed focus and was fast at it too with everything. Feel betrayed cause i though was doing what they wanted And now afraid its gonna happen again. Still cant figure why they did that.

one day my mind just had mental break down and my anxiety i just went panicked mode cause i had to go work and just couldnt go and stopped going .

My question is What is wrong with people ?

why do people care so much to destroy other people ?

Need help in trusting others