I assume you mean over populated by people because there are far more germs and insects than people on Earth.
In fact, we have very few people, but we are a destructive people that are capable of and are in fact changing the environment and not for the better.
Without population control it will just get worse and worse. Every heterosexual couple should have no more than 1 child. This would reduce the population and allow us to continue to abuse the environment and enjoy our pleasures of modern civilization at a sustainable level. However, in absence of that it will not get better and it will come to a point where there is a crunch. Sooner or later things will crash and eventually nature will balance things out.