Shedding on a flat-coated cockapoo?

I recently got a 12-week old flat-coated cockapoo from a cockapoo breeder (from whom I also got my other very low-shed curly cockapoo who is now 11-months old ). I understand breeders cannot guarantee their puppies' coats and temperaments. I also understand that a flat-coated cockapoo must have taken more traits from the shedding cocker spaniel side rather than the non-shed poodle side. But my new flat-coated cockapoo is shedding like crazy. A groomer told me (and the vet confirmed) that the dog might just be nervous or anxious because I just got her a week ago. Can anyone share with me their expert knowledge on why a dog in general (regardless of the breed) might be shedding? Do most shedding breeds shed more in the summer months? I plan to ask the vet for more possible causes of this shedding when we go back for the puppy's next scheduled vaccination shots. For now, I am using the Furminator daily on her to reduce the shedding and it does somehow help but the shedding continues anyhow. Any other 'treatments' you can recommend for my new pup? She is a very beautiful, sweet, gentle yet spunky, easily trainable little pup and I hate to just give her up simply on the basis of her coat-shedding. I do not 'judge' nor 'reject' people based on their physical characteristics and I do not want to do that to this puppy.