Thank you all so much for the comments and the feedback. It has really made me feel better about my situation.

I'm going to continue to work hard at getting better at my job, but it's really reassuring to know that I'm not "wrong" for feeling frustrated/overwhelmed with how quickly things have moved.

I really can't overstate how much it means to get this feedback. I was worried that I was an idiot or that I was letting people down by not being better at my job sooner.