My previous job was a full stack developer, but I had built the entire product from front to back on my own and knew how it all worked. I found it quite easy an

My previous job was a full stack developer, but I had built the entire product from front to back on my own and knew how it all worked. I found it quite easy and even enjoyable. Now I'm working a job that is not full stack and I'm finding it extremely stressful because I didn't build the thing and still haven't figured out how the different parts work, much less work together.