Thanks for your question on Healthcare Magic. I can understand your concern. Precautionary pills (contraceptive pills) are made up of hormones. On regular ingestion, they cause hormonal imbalance which is not favorable for pregnancy. Sometimes this hormonal imbalance can cause side effects and complications like gastritis, intestinal contractions, weight gain etc. All these symptoms resemble pregnancy. Since your ultrasound and pregnancy test are negative, your all symptoms are due to side effects of pills you are taking. So consult your gynecologist and ask them her to change method of contraception. Hope I have solved your query. I will be happy to help you further. Wish you good health. Thanks.