Strange pain in crease of my upper right thigh?

yikes! You really need to go see a doctor. It could be gastrointestinal upset, but it might also be toxic shock syndrome from the tampon. I had ovarian cysts (2 huge ones that required some radical surgery) that caused some severe strange pains in places far from the ovaries. Perhaps the pills are reacting to something? Could you have an ectopic pregnancy? Wow. Please go to an urgent care facility or emergency room. Urinary Tract infection? I could speculate forever. Just go.