Severe cramping?

I’m 7 weeks 4 days. I’ve been having inconsistent light cramping most of my pregnancy so far and other symptoms including nausea, headaches, sore breasts. This afternoon I was suddenly doubled over in severe cramping pain in my stomach. It lasted maybe 10 minutes. TMI: I did have a little gas during this and I tried to poop and hardly anything came out. I’m sure I’m constipated, but is that what this is from? I’m so scared it’s something bad. I have my first ultrasound scheduled for 2 days from now.