YA scary novel about a girl getting sent back in time to regards of a witch

[Bree]

So I am looking for a young adult novel I read when I was a kid (reading books that gave me nightmares) and this was my moms book. I don't remember much but I think the plot is a girl who gets sent back in time either untentionally through her dreams or through a doctors session she keeps visiting.
Mystery/horror set in the states? SET IN SECOND POV I THINK
Adult single book about girl time traveling and some scary doctor

The doctor does play a big part in it in the sense that I SPECIFICALLY remember a scene of her explaining time travel to the main character with a string saying the energy becomes enough and—the string loops. I also remember the word velvet in the book for some reason.

The book was a small soft cover, all black with the words red. The title was something simple like 'The Nightmare' or vice versa.

I think there's a witch? Either the doctor is secretly the witch in the nightmare or what, I do not remember. But I want to reread this book and I cannot ask my mother. I read it in like 2009 but the book was like as old as 1960s-1990s.

[Kris]

Bree, when the girl is sent back in time, where does she appear and what is the time period? Does she appear as herself?

Is her doctor referred to as a psychiatrist or psychologist? Why does she visit him?

[Rainy]

Might help narrow is down if you can remember anything specific about what she does when she travels back in time. Anything significant there?

I know it’s hard to remember stuff like that but it would really help narrow it down if you could remember anything about what happens or why she’s going back in time. Or is she just dreaming?