New cat is traumatizing me

I was recommended by a therapist to get an emotional support cat. I have anxiety issues and have previously owned a cat that helped those issues. I went to a local shelter and went with someone I know who has an ESA to find a good fit. After meeting lots of cats, I adopted a male Siamese mix about 2 weeks ago. He was very affectionate and independent and seemed like the perfect fit. We bonded immediately.

The day I picked him up, I noticed him trying to bite (in a playful way) my brother’s ankle in the shelter. It stopped and I didn’t think anything of it.

Fast forward two weeks and the play-aggression turns out to be a serious issue. I find myself unable to walk when he switches into play mode because he will attack my feet. I upped playtime and switched up toys, redirecting every time he bit or tried to bite. I began trying to ignore him after the behavior, but he didn’t care at all. Not one bit. He doesn’t care about toys. All he cares about it attacking me. I know he’s not bad, and that someone clearly taught him this was appropriate behavior. In fact, he can be quite loving. However, he can turn on me very quickly and it’s terrifying.

Yesterday it escalated to him trying to bite my neck, then proceeding to go after both my arms, and when I removed him he began to immediately go after one leg and then go after my other leg. I became very afraid because I could not get him to stop, and I got him off and ran out of the room. I proceeded to have a very bad panic attack and couldn’t calm down. I spent most of today crying because I’m terrified of a cat that loves me. I have health problems that make it very serious should his bites ever break my skin. I went into the room where I have his litter box and food, but began shaking so badly I had to have someone come with me to keep him busy while I took care of him. Every time he approached me I began to panic and cry, begging my brother to keep him away. I am an adult, and I feel like I should be better than this.

I feel like a horrible person because I know what the issue is and how to fix it, but it requires me still having to get bit while the problem is being fixed and his attacks are not something I can handle. I couldn’t let any of the farm cats outside (he’s a strictly indoor cat) near me, the nicest and sweetest cats alive, because he’s made me so scared. It’s only been a short time, but I don’t think I’m a good fit for him. I called the shelter I got him from to see what I should do, but the woman made me feel like a horrible person for thinking about bringing him back. I have awful guilt over this, as I am causing distress to him and myself. Part of me wants to push through, but I’m not able to sleep or eat and these panic attacks are some of the worst I’ve had. And he deserves better than that in a home. He needs someone who can work with him.

Am I making the right choice? I know this is a lot but I’m scared and conflicted and have no idea what to do.

I don’t even know if I could ever get another cat after this and I have always loved and done great with cats.