I think it is normal. I had one who just screamed bloody murder when I left him alone. I think it is best to start teaching them right off the bat that they will be left and it's okay. I think it is totally normal for a baby to try and alert its caretaker that it thinks iit has been forgotten. They don't know any better.
They learn by repetition of being left and us coming back but if they scream the whole time then they think their screaming brought you back. So you do have to wait them out, which is hard. My one was tough but we got through it and he is a totally balanced adult now who is fine to be alone loose, crated, kenneled, in the home, the truck, wherever.
Had I not worked through this with him when he was teeny I dread to think how awful he could be now that he is a 90lb dog. I remember him grabbing his crate bars and biting and pulling but he did not have the strength to do anything, now imagine if he still had that behavior as a 90lb adult? Persevere!