New to this and need advice

I stopped taking birth control on Dec 25, 2018. I couldn’t be pregnant now right? The <a href="">glow app</a> says i have a high chance of being pregnant but I haven’t even had a normal period. I had spotting that lasted 3 days and then back to normal until yesterday. Yesterday nausea and cramps started and today, Lord have mercy - If I’m not cramping, I’ve got nausea, throwing up and diarrhea. As soon as it happens I’m fine for a couple minutes then back to feeling like PMS on overdrive. Could this just be my body adjusting to my new normal of no bc - it’s been a while since I had a normal period? Or could I be pregnant? Is it too early to test? How long should I wait to test given these symptoms?