5 month old puppy throwing up in kennel when left alone.

Hi, My 5 month old pit bull is starting to get separation anxiety and throwing up, a lot, in his kennel. I don't know what to do since he is still a pup and I don't want him getting into anything while we're gone. And I also have 3 other dogs, my oldest two are left out of kennel and my daughter's 8 month old Heeler pup is also kept in his own kennel while we are out of the house. Any advice would be much appreciated! I had a chow chow mix who use to make herself sick whenever we kenneled her, but by 5 months old we were able to leave her out of kennel without worry and she was also the only dog in the house at the time.

5 month old puppy throwing up in kennel when left alone.