I got out the shower and it was very hot an steamy I felt very weak dizzy an felt to be sick I've had a period what's going on?

Normal tone response. About 60% of teens either faint or have dizzy spells. Most are a normal autonomic nervous system response: change in position, quickly standing, standing for length of time, hot showers, hot tubs, hair combing, yawning, swallowing, stretching. These all can cause a decrease in blood pressure. Stay well hydrated and increase salt intake.