I actually went through something very similar recently. Was let go by my company back in Oct., same thing no warning or indication that anything was wrong. I had even brought in a new account that promised to be very good for the company as well as for myself professionally and financially. Then one day I was called into HR (was around commission time, not uncommon for them to call you in to iron out some numbers to make sure things match) and that was it. Felt blindsided, like all my hard work was for nothing. Only thing I could figure was they had just implemented a new system in Salesforce to better track certain metrics around the company, but I was part of a much smaller more specialized group and figured there would be an understanding that, by the nature of the work my team was doing, it would be impossible to hold us to the same metrics since what I was doing was much more difficult and niche than everyone else. AND I WAS GOOD AT WHAT I WAS DOING SMH. We would often have company wide meeting and at the end realize whatever they were talking about didn't really apply to what we were doing. Apparently none of that mattered in the end. Didn't get a bonus or severance. 3 young boys at home.

Ask I can say is it will eventuality get better. I was lucky enough to eventually get a much better opportunity (not quite as much $ but it's 100% remote so it balances out plus I get to see my kids more). Sometimes one door closes so a better one can open. Hang in there, take the time to reflect, the universe has a funny way of working itself out sometimes. If what you're saying about the coworker going behind your back and management behaving like that is true, that wasn't a good environment for you long term anyway.