What Causes Bloating, Missed Period, Dizziness And Lower Abdomen Ache?

Hello, I am 22 years old and I am on marvelon (have been for a few years). I missed a few pills last packet and the packet before which i took back to back. My period is now 1 week late (just had some light spotting a few days before it was due) but pregnancy tests have shown up negative. I have never missed a period before. I am bloated, have nausea and dizziness. I also have some dull aches in my lower abdomen. advice?