I have a cocker spaniel which has growled at me and I am afraid. What do I do?

I had a bad bad experience with a very young cocker spaniel last year; he began to attack and bite me after his first vet appointment. He tore my skin and I had to put a muzzle on him, hire a trainer, and still he continued with a low growl when I attempted to play with him. I found a rescue that was willing to work with him (two veterinarians thought he was severe enough to be unsafe and recommended putting him down rather than putting him in a shelter where he might end up becoming so fearful that he would not be adoptable[he was a real honey most of the time]}. It took a while but they found a person who was comfortable with working with him for the rest of his life and he is in a great home now. I really loved him, but he injured me on several occasions. Two months after I gave him up, I adopted a large senior golden retriever who was an abandoned stray. He was very quiet and I have grown to love him, but he was not cuddly. I decided to look for another cocker spaniel but to find one that was a little older with an established personality which was not dominant. I have always thought I am fine with dominant dogs, but I had never been attacked and bitten and now it is like a fright valve opened in me that never was open before. So. After another couple of months of talking to various breeders with older cockers, mostly retired breeding females, I found a puppy that was 5 months old. I talked to the breeder. She described him as a cuddle bunny, not aggressive at all, mostly house broken, and great with other dogs (besides the other cockers, she had a newfoundland). She sent me loads of pictures of him, playing with her grandson, being groomed. I drove down and met him and he was all she said. But, and I did not listen to my inner voice, I worried, what if he becomes dominant and bites. Still I took him. For 2 weeks he was perfect and I was beginning to really relax around him. Suddenly, he began to attack my rescue golden. It escalated. I was on the phone almost daily with the breeder and called the trainer who had worked with the other puppy. The trainer was appalled that I had gotten another cocker and chastised me and told me just to return him to the breeder, that the breed is bad, why not get a King Charles Cavalier spaniel (which have some pretty dreadful neurological problems and heart problems). At first I was so shocked at what she said, I decided to give the puppy back and then just like that the aggression stopped. Boom. The Golden is not the alpha, the cocker is and it is established. They play, things have been just awesome. I have a cuddly wonderful cocker whom I trust. This Sunday my adult daughter who has a chronic illness came for a visit. This was not the first time and often she is whiney when she visits. She moved from her seat onto the couch next to the cocker who was between us. She was trying to show me something on the computer and I could not see the screen. I told the pup to get off and he did not move. I put my hands under him and began lifting him off and he growled and snarled at me. I got him off and reprimanded, no growling. Later he was on the couch next to me after my daughter was gone and I needed to move him and he growled again. First off this is Thursday and for the whole week I have felt frozen around him. Is that an over reaction? Probably. I do not want to have to do the whole I am the boss thing again. I trusted him so much and now this. So I had a thought. Let's just avoid the problem by getting him off the couch with a reward when I tell him. It has worked. If I am sitting and I invite him up and a while later I need him off, I just say, Get on off, in a high pitched friendly voice and when he obeys I say good dog etc. No growling now for 3 days. But I am totally afraid inside. How on earth do I get over this fear? The trainer may have been right and I was a fool to chance a cocker again, but it is too late now. The breeder has told me that she will take him back no matter when, no matter the circumstances, so I never have to keep him. And with this feeling of not trusting in my belly, I don't know what to do. He was growling at the golden and leapt up to nip him and at the same time I bent over and his open mouth touched my face. He instantly pulled away, not letting the nip happen. So. He is not my other cocker. But I am so anxious. What do I do to calm myself down.