A few of my toenails have always grown out layered, thick and yellow. they like die really fast or something because they are layered so much that they are rounded. ive tried fungal medicines/prescriptions but it hasnt helped. what is causing this?

There are a few possible causes. See a dermatologist. Good luck.

You describe a common final infection of the toe nails ( recent studies show bacteria also involved ). Very difficult to resolve. If healthy oral medication usually required to resolve the problem. But if infection clears you will need to use preventative measures because your immune system is weak in preventing infection. See a podiatrist for care diagnosis and treatment.