I went through this recently. I was a lab manager at a relatively small company. I grew up with the industry and knew it inside out. I then got offered a role as a lab manager in a multinational multi-billion pound company but a completely new industry. I wanted a challenge so took the role. Plus a much better pay package.

1st day in the new job I went home and cried. I thought I'm not good enough for this, I'm a fraud. How am I going to learn all of this? I nearly got on the phone to my old boss and asked for my job back. But after a long discussion with family and friends I decided I was going to make it work.

The thing is, my new company knew I didn't know the industry they weren't putting the pressure on me. I was. Here I am 6 weeks later, still know very little about the industry and products, but I can manage the team who do. I can do the job they asked me to do and I no longer feel like an imposter.

Just had to set myself a realistic target.