When you first start taking the pill, the hormones can make you feel very different. Many people get pregnancy symtoms the first 3 months of being on the pill and then your body will adjust. If you really feel like you could be pregnant even after getting a negative result at planned parenthood, then you should make a doctors appointment for a blood test since that is more accourate. You should still take the pill in the mean time. If you are pregnant, then stop taking them when it is confermed. The pill will not do any harm to a baby if taken for a short time.