Hello, You are 25 and are suffering from low energy since 2 months. You are on contraceptive pills and have also gained weight. Low energy is commonly caused by thyroid dysfunction, get T3, T4 and TSH done. Get clinically examined and get treated. Other causes of such symptoms are anemia, general body weakness, stress (emotional and physical), dehydration, hypoglycemia, low BP, etc. You are suggested to take adequate water and fluids, do not skip meals, take home made food rich in iron and minerals. Avoid anxiety and exhaustion. Take quality sleep at night. Avoid sedentary lifestyle. Do regular walking, exercises and jogging. Yes contraceptives may cause weight gain due to water retention, fat gain, increase in muscle tissue. However, water retention can also be due to various reasons like deep vein thrombosis, varicose veins, kidney problems, heart problems, etc. You should get clinically evaluated and treated for medical cause causing weight gain. Stay away from addictions if any. Take care. Hope I have answered your question. Let me know if I can assist you further. Regards, Dr. Nupur K., General & Family Physician