Side Effects VS Severe Side Effects

This is confusing reading about all of the side effects of TC. Some of the call your doctor for examples are the same side effects that are listed as possible and normal. How on earth does a person tell the difference? The stomach ones are not so easily identified. If I can't breath or have chest pain, racing heart etc those are easy to identify.
I read about nails lifting. Does the nail actually come off, get loose, sink in, start peeling or what? Is there anything one can do about it?