Can I sue for ruining peace and enjoyment ?

You asked this yesterday. ONCE is sufficient.

"...spoke to one of my lawyers..." Then you don't need to ask us.

Is the dog owner liable?

Is there a leash law in that jurisdiction? Can you prove you were not speeding, distracted, etc? Do you know who the owner is? These are some of...

You need to file a replevin action or its CA equivalent, and prove the dog is more yours than your ex-friend's. Given that it was a joint...

I’m about to be evicted out of my cottage- 30 day month to month. She is allowed hOWEVER she has been harassing me since day one

The time to have objected to her interference was long before the eviction, which makes the issue moot.

Can I sue for veterinary malpractice/negligence?

You are alleging medical malpractice - moving accordingly. You need the other vet to testify that the first vet failed to provide the accepted...

"my ex friend in Ohio gave me a puppy" If that is all there was, other than sending photos, the dog was a gift and is yours.

Who has ownership of dog?

What "agreement?" Is it even in writing, still less signed? Do you have a receipt for the 50% you supposedly paid by Venmo? "In MA, the dog’s...

Read your contract, as it may have a mandatory arbitration clause. Review it and the record of failures with an attorney versed in consumer...

Check the CA "puppy lemon law." For your sake, I hope this was not an internet/out of state purchase.