It appears that you are possibly facing some tummy trouble perhaps somewhat associated with your very first sexual encounter but not as a direct result of it.  The aching, vomiting, tiredness, and frequent bathroom visits might be due to a tummy bug or infection. The zit on your skin could likely be caused by hormonal variations. You must take a lot of water, get enough rest, and eat plain easy-to-digest items like bread or rice. If the situation does not change please visit a gastroenterologist.