Puppy cries endlessly

Hello. My husband I got our first dog, a springer spaniel, 6 days ago. She is 8, almost 9, weeks old and we are currently in the crate training trenches. We have a crate that is covered and a small space appropriate for her size. Whenever she falls asleep, we put her in the crate so that way she knows that is where she sleeps and is a safe place. She does great with this during the day when we are home. The problem we are having is night. She can’t seem to be away from us without crying, whining, absolute squalling. It sounds like she is getting mauled. I don’t think it’s separation anxiety? Or maybe it is? She can be outside by herself just fine (I keep a close eye on her when she is by herself). Anyways, the breeder told us to put her in her crate, covered in a back room and let her cry is out for probably 2 nights. Me and my husband tried it and she cried nonstop for over an hour before we went in there. I feel like this would cause more damage than help? Am I right in thinking that or does the breeder have a good idea. Me and my husband have been present with the dog since we got her but we will both have to leave for our job in 3 days. My MIL can check on her mid day but I feel like I’m running out of time to prepare my pup for that. Any advice PLEASE!