Feeling stupid at a new job

I've started a new job a month ago. I'll share how my feelings are so far because it might be that other engineers feel similar when they start (or move into) a new job. They don't teach you what your brain will experience as a rookie. Furthermore, people won't talk about their feelings at their workplace; it's considered unprofessional. Well, if these lines can help someone, my mission will be accomplished.

Bear in mind that we are all humans trying to do our best. You might think that you are the only one feeling weird at a new position, but I suspect that everyone feels vulnerable at some point in their career. Extroverted people might endure those feelings better. On the contrary, introverted people will experience a spectrum of uncomfortable sensations—I'm on the extreme. Probably, I'm the hugest introverted in the meeting room.

In my case, most of the uncomfortable feelings are related to the word inadequacy. As a new member, everyone seems so articulate and clever to me. I ask myself constantly if they ever make mistakes. Then, I wonder why some of the simplest tasks I'm required to do are taking so much time. I'm constantly afraid and anxious that they might think I'm slacking off. I even skip breakfast because of the regret I experience when I'm not working. I feel like everyone is overwhelmed, and I'm doing pointless tasks. After a couple of weeks, I feel even more stupid, and I wonder if I'm a good hire for this position. I can't even think clearly! What's happening with me?

I've been working alone for such a long time that I find it difficult to reach out and ask for help. I've always done things by myself, making decisions, and now I need to talk to several people to get something done in agreement with the whole team. At meetings, I catch 30% of the explanation. I would rather receive a mail to be able to read the statement several times. Again, what's happening with me? I've always been able to think outside of the box and solve things creatively. Here I'm not able to do it. I would need to rewire my whole brain to fit in here. At night, I can barely sleep, because I'm anxious about the task that I need to do for the next week. What if I'm not able to do it with excellence or on time?

Well, these are my feelings so far, as honest as I could. I reckon that these feelings will fade over time (around the 6-month mark). I'll talk about it later on. For now, let's live with this discomfort.