What is the difference between pregnancy symptoms and pregnancy symptoms that the pill gives?

Pill vs. pregnancy: BCP's today are a fraction of the strength of the ones first used, and even those of the 90's, so the "pregnancy like symptoms" are minimal, since the ovaries don't work when taking them. In contrast, the estrogen/progesterone levels in pregnancy are extremely high, and cause breast tenderness, mood changes, weight gain and water retention which are far more obvious than pill effects.