[New to yorkie]

Hi I'm new to the site so I guess I can just tell you my experience. I have a 3yr old Parsons Terrier who is crazy lively but he is adorable about 4 months ago we got a little yorkie boy he was approx 10 weeks old. My parsons is a solid muscly dog and the pup was tiny. To cut a long story short initially my Parsons was pretty hyper barking a lot, we didn't change none of his routine we kept everything the same for him to reassure him. We had a pen that we had the pup in and gradually we let them spend time together, I won't lie it was a full time job watching them all the time, but what I found is if I was anxious around them they were more crazy, so being calm is a great thing. Today my pup is 6mths and we have no pen, they do play rough sometimes but they are now buddy's .
I felt so guilty also but I had to take the pup to another room to spend time for basic training and cuddles at first but now they are happy together.
It takes time and patience and I'm not saying everything I did was right but I'm sure you will eventually have two happy buddies. The guilt will go when you see how happy they are together