What Causes Bloating In Stomach And Swelling In Ankles And Feet Before Periods?

Before 4-5 days of periods I feel like I put on weight and fat in my lower abs & also feel like my stomach and lower ab become very heavy and bulky and also feel tight as if gas filled inside. But after periods start then 2 days later I feel like my stomach become light and easy and I feel relaxed and comfortable like I lost 2-3 kgs of weight. I am suffering from hypothyroid and insulin resistance since last 2 years but I think this problem was before this. But after being diagnosed with thyroid and ever since my weight has been increased, the problem become more worse. (I haven't tested PCOS or PCOD recently but last year I tested and it wasn't found in sonography) Also before periods I feel like swelling in ankles and feet and after periods swelling become less. However due to thyroid swelling in ankles is often but during pre-menstruation time or if I eat something citrus like imli chatni then it become worse. After periods, I feel like swelling disappears. However after few days it will be seen again. I am taking thyronorm 50 mcg but haven't started taking glycomat 500 mg yet as prescribed by doctor.