I've recently started a new job after working for my previous company for a decade. I've gone from being an expert in my field and quite bored of the day to day to knowing nothing in my new sector although the job role has some overarching similarities. I've recently had a baby and remember from my first baby that my confidence was severely impacted for a while afterwards but I'm really struggling with the new job. They don't give me much direction and hardly anything is recorded to let me learn it myself. I'm spending a lot of time doing theoretical reading on the new sector and feel not much is going in because of sleep deprivation and the fact I haven't spent a whole day reading academic articles since my student days, a couple of decades ago.
Every time I try to get involved or make a suggestion I feel like I'm so unqualified and just talking rubbish. They haven't said anything about not being happy with my performance but I don't really know what to do. It feels like a big mistake to leave my previous job right now even though it made me miserable too