I don't even know who to ask for help so I thought I would turn here. We have a 2.5 year old dog that we rescued when he was 10 months-ish. Up until like the week I got a positive pregnancy test (which was most likely a coincidence but who knows) he has been awesome. He never has accidents, loves people and other dogs, great with kids, follows tons of commands, walks well on a leash, just all around a great dog.

We send him to an awesome doggy day care, he has been going there for over a year, once or twice a week most of the time. Then he started being mildly aggressive at doggy day care, and now we keep having incidents at the dog park. It isn't all of the time but it is happening enough that we are concerned. He mostly barks meanly and growls and sometimes starts a scuffle. He comes away quickly when called and we always leave immediately. I don't think it has happened when just my husband has him (and he adores my husband and definitely sees him as pack leader).

So now what? He is really well trained (obviously other than this new issue) and still behaves beautifully at home and on walks. I am bewildered and just want to fix it, he is a super high energy dog (40 pounds and some sort of herding dog mix) and he needs to run around, and normally loves playing with other dogs.