Can you say less to your coworkers so that it doesn't go straight to your boss? Just keep to yourself at work, do your work and focus on that and that alone?
When I get overwhelmed like you feel, I try to focus on literally getting through one day at a time. Focus on the here and now, and on what needs to get done today. Then rest after work, take it easy, do some self care activities, eat a nice meal, get plenty of sleep, and then when you get up, focus only one what needs to be done that day.
Getting bullied is a horrific experience. I've been there many times at work. Can you look for another job? Often times, the best answer is to just leave the position but only when you have another job lined up.
I know it's really challenging to job search while you're working full time, but you can in your free time and just make it happen. That's what I've done whenever I've been bullied at work. As soon as it happens, I am looking for another job.
Often there is no recourse for bullies at work. Going to HR is a joke. HR isn't about the employees' welfare; HR is all about the company's well being and success. They brush things like that under the rug and often it puts a target on your own back if you go and complain. So there's no point in that.
I would just try to find another job somewhere else, keep your head down, stick to yourself, take it one day at a time, and do a lot of self care in the meantime.
Hugs to you. I feel for ya. Hang in there!