What Causes Headache, Indigestion, Spotting And Tightness In Uterus?

For the past week i havent felt right. I've had a constant headache, nausea, and some indigestion. I got a two day bleed followed by A day of spotting around a few days before my period. I backtracked and realized I had unprotected sex almost every day of my fertility period. I also have strange cramps that feel like air bubbles, & some tightness in my uterus. I've tested and got all negatives this far. What are my chances of being pregnant? I've never had children and I've never felt this way before