So I joined this digital agency where they are working on this ad-tech product and right from day one, I was given a task to implement a new feature on the product. No knowledge transfer. No onboarding process. So, I had given estimation about the task and apparently it took longer than expected. But what were they expecting. Anyways, my manager asked me to have a KT with the only senior guy that has been working there for last couple of years. And man, since the KT started, it's been hell for me. The guy is such an asshole and won't even give me a basic walkthrough of the system. He only took one call and that ended within 30 minutes. On top of that he went ahead and told the product manager that I am not keeping up and am not ready. And my product manager apparently wants me to take his place within a month. It's been only two months since I joined. I have already pushed two major features, tried to understand the system architecture, codebase and everything on my own. On top of that, I got yelled at by that senior dev in a meeting about a PR. I was quite confident guy when I joined and now I am anxious everyday at work and i am scared that they'll let me go because I won't be able to meet their unrealistic expectations. I also can't stand this senior dev and he can't stand me which makes me really demotivated to work. I have anxiety issues and now I am thinking if I stay, I am gonna mess up big time and they'll fire me or worse. I might break something in production because I didn't have proper onboarding.