Answer 1: It is better to AVOID taking HCG drops during your menstrual cycle as it can slow down the menstruation.
Answer 2. You will notice mild headaches, depression, blood clots, dizziness and, in some rare cases, might lead to ovarian hyperstimulation syndrome.
Answer 3. On the contrary, you might gain weight or stay in the same weight till menstruation cycle is over. This is normal and you will start losing weight once you resume with HCG diet drops post-menstruation.