I stopped taking birth control on July 9 and immediately started bleeding the next three days after. For the past 2 weeks I've have cramps but no period and have had nausea, dizziness, sore nipples, and creamy white discharge which all have stopped but the discharge and cramps as of the last two days. I've taken two pregnancy tests on August 8 & 11 but both were negative. Could I still be pregnant or are these signs of stopping birth control?

It could be, but it could also be pregnancy. You tested too soon unfortunately. Most tests are best taken about two weeks after a missed period. The problem now is when is your period considered missed since we're not quite sure when it should have started. I would wait two weeks and try again. A lot of the early pregnancy symptoms are identical to a those that come before a period so they're not really reliable. The best and most reliable symptom is a missed period. It is a bit of a waiting game at this point I am sorry to say.