I am 17 years old and is not sure what's going on with my body right now. My breast are tender and I feel bloated like I gain weight. My period recently ended but instead of lasting 9 days, it lasted for 6 days. My last two period were light and there wasn't any cramping. I'm so confused because I haven't had any sex. Yes, I have a boyfriend but all we do is kiss. I wondered if your body changes when your in a relationship. Please give advice as thinking about this makes me sick and feel uncomfortable because I don't know what's going on. Thank You.