Feeling Nauseous, Diarrhea, Sweating, Heartburn After Unprotected Sex, On Tri-Sprintec. Could I Be Pregnant ?

my boyfriend and i had unprotected sex last wednesday afternoon around 1. that night i went to dinner with my parents at souplantation and took my first pill of my fifth month of tri sprintec at 6pm. At 3am the next morning i woke up feeling nauseous and threw up a few times. I had diarrhea, sweating, and shaking/chills. I thought it had to be food poisoning. The next few days I had been unusually gassy. But for the most part felt fine. Then last night, I ate rice with a lot of sliced garlic in it, and got really bad heartburn. I have acid reflux disease so ive had heartburn before, but never this bad. I couldnt sleep much due to the feeling that i would throw up. I got maybe four or five hours of sleep total. Today I also dont feel that great, but Ive also been thinking about the possibility of being pregnant. Ive been very thirsty, but still have a dry mouth when i drink. I have diarrhea and occasionally constipation. I took a clear blue pregnancy test today and it came up negative however I am worried that it is not accurate because it is too soon. Could I be pregnant, or could I just be over thinking and worrying too much? Or is it possible to still have food poisoning, if thats what it was?