I have one head, one foot, and for legs. In other contexts, I can be found be a river or in a garden. What am I?

A chill down your spine, visions invade your thoughts, you saw it all so clearly but how? Do you say something or wait since it hasn't happened yet.

Treasure is on the tip of my tongue, but if you're like me, you'll never tell

Find me, and you are new. Give me, and you are now three instead of two. Write me daily, or speak me daily, to let others know me. What am I?

I'll almost always sink in water, no matter how many times I'm skipped I could roll or just sit there, depends on my size and shape I'm almost everywhere in some way If you can't get this you might be between me and a hard place What am I?