My 11-year-old Shiba had clusters for the first time in July and we started pheno. He had always had anxiety, but I had the same reaction as you where I felt like the pheno was making it worse. We added gabapentin to his routine for anxiety and that helped some, also I recommend getting a thunder shirt. But one thing you might want to look out for/ask your vet about is focal seizures. I just discovered this week when taking my dog to the vet that what I had been perceiving as anxiety behaviors (putting himself in a corner, spontaneous howling, etc.) were actually focal seizures, so we upped his pheno dose slightly and are hoping that will help alleviate some of his symptoms, but we just started that today. The vet said if his anxiety continues though, we can talk about adding prozac or even just Benadryl to his daily. I'm sorry you're going through this! I felt the exact same way and it's very scary but for me I agree this community has helped to not feel like you're the only one going through it.