Hello,
Welcome to ehealthforum and thanks for writing
If you have started the birth control pill recently(less than 3 months)then the symptoms explained by you as spotting,nausea,cramping,irregular bleeding/discharge could be due to hormonal changes in the body due to pill intake.These effects are quite common after pill use and subside after few months.
If you have been taking the pills regularly then relax and continue the pill intake.Avoid unprotected contact if you forget the pills in a row.
Take care!