It would sure seem that it is the birth control that is aiding your differences.
Consider just going off of it for awhile or changing birth controls to see if it was just the one that you were using.
The pain during sex and weird discharge could also be small signs of an infection, such as a yeast infection or BV (bacterial vaginosis). However, itching is a more common sign for those, and birth control could cause strange discharges as well.
I would head in to see your doc and ask what he/she thinks.
Many women can only use one type or kind of birth control because their body cannot simply act well on any other, so I would have to say you've found the cause of your problems. Just head in to see your doc to clear them up!
Good luck and Best wishes! :)
Bcp's can most definitely make you throw up and have swollen, sore or weird breast/chest pains, anxiety and depression. The best advice I could give you is to try switching to a lower hormone birth control pill. Or another bcp, in general. Just experiment and see what works for you. Good luck!