On contraceptive pill for nearly 4 years. periods for past 5 months have been extremly light. is this normal after 4years? very worried.

Normal: Yes this is normal. Birth control pills (BCPs) have higher progesterone effect than estrogen. Not only do they prevent you from ovulating but they also prevent your uterine lining from building. This will make your periods lighter especially over time. Your cramping should also be less. It's important to try to take the BCP around the same time every day to maximize effectiveness.