There is plenty of information about this in trusted sources, the way you're describing this is incorrect. Overcorrection and badly designed simplistic optics can make myopia worse in childhood when the eye is growing. Your eye is no longer growing.

Don't trust everything your doctor says verbatim, they often oversimplify and their information can be out of date. Give your doctor the benefit of the doubt but check it against other sources and use it to build a mental model.