Is our adoption failing or is this normal?

In August, our adoption prayers were answered. Our 6 yr old son moved in with us after a very quick transition period of two weeks. Although the our transition seen abnormally quick, We had a smooth transition, everything was PERFECT. He was sweet, and kind, and loving , very loving. This scared us, because he was telling us he loved us very very shortly after we met him. But naively thought maybe it was just meant to be, a perfect match. We had a beautiful complete family. Like every family, we had a few issues, we had to set rules and boundaries but he was good about following them we were all learning our family dynamic together. Then, he had his first tantrum. It happened at the 2 month mark, almost to the day. It was aggressive , violent, things were being thrown, he was screaming at the top of his lungs he was uncontrollable, We were in shock. The next day I contacted my worker and immediately asked for help. (Public adotpion, we are two months into our year probation) He had not had theses type of tantrums at the foster home but he did have failed adoption and these types of tantrums did happen there. A week later the second tantrum came, and again, things were being thrown , it was aggressive, very angry and the look on his face was shocking. It was as if he was another person. We called the foster mom during this one and she was able to calm him down. The very next morning the third tantrum came and again, spitting, yelling , kicking chairs and a lot of laughing. I was alone for this one, terrified and shaking. I called the worker this time and within a few min she arrived to help calm him down. (Which he was by the time she arrived) Our worker suggested a crisis intervention centre thAt day and we spend a few hours speaking with a counsellor. He barely spoke at all, said I don't know a lot and we were sent on our way. We found out that day he had a file there, he had been there before. I spend the entire day looking for help (ontario canada) and found nothing, just several waiting list, a lot of reading information. We have asked our workers for help, we are begging at this point. But they seem to think this is just testing. We're not crazy, we expected testing, we knew it would happen, but we didn't think it would come with such violence and anger. We have very limited information on background, because again our workers haven't been very forthcoming with information. The problem is, I went from being over the moon excited to a dead stop. I feel like a terrible person for admitting this, but I'm terrified of this child. We feel we were lied to by our workers. I feel like the connection I had with this child has been replaced with fear, I'm walking on eggshells, I fear upsetting him because I know I cannot handle the severity of the tantrums. It breaks my heart and I feel terrible that I'm even thinking this, but we may not be the right family for this child. My husband has the ability to shut the tantrum out after its done, and I remain in shock and angry and live in fear for hours. I can't return to normal the Instant our child's decided he's done and wants a sandwich. I'm desperately hoping to connect with other families who are questioning their match, or have a child with an attachment problem.