Nauseous and negative?

I stopped taking the pill September first, 6 months after my sun was born. He sleeps through the night and only nurses three times a day for about 30 minutes each feed. I haven't gotten my period and I feel so nauseous and am throwing up for about week now its come and gone. Ive taken multiple test that all say negative. Anyone else with a similar experience? What's going on with me right now? Help... I just want a positive test or my period so I at least know my system is working right....