Cat died after possibly ingesting something poisonous?

Four days ago, after being fine all morning, I noticed my cat was uncontrollably drooling, and sitting in one spot acting strangely. I tried giving her water, and cleaning the drool off, but she continued to drool constantly. I had no money to see a vet, and scoured the internet for answers as to why this was happening, and prayed that she was just going to throw up, and be okay. After about 40 minutes after noticing her drooling, She went into some sort of seizure/fit (meowing and jumping into walls accompanied by very heavy breathing, then just laid on my bathroom floor. after about ten minutes of sitting with her on the floor she died right in front of me. This is by far one of the hardest things I've ever been through, as I loved this cat very much (took her in as a stray about 8 years ago, and for some reason she only seemed to trust me out of my family, and was very skittish around others. Yet, she slept with me every night, and would practically never leave me alone. I'm assuming she had a history of abuse.) As my family didn't have much money, we weren't able to take her to the vet, but knew that she had obviously been spayed, and such. She could have possibly been up to four years old I'd say when we took her in. I took very good care of her, and she was always happy, and healthy seeming. (forgot, she looked to be an almost pure-bred Persian cat). My question is that after her dying, I noticed a spot where she had been drooling right before dying, and it looks almost as if there is glitter in it. I can't find anything with glitter, or anything like that in my home. Anyone have any ideas. I'm hoping this was a death due to some sudden illness, or freak occurrence, rather than poisoning, as I'm having so much trouble dealing with the guilt of not being able to take here to a vet.