Did I have a miscarriage?

I took 4 tests and they all came back positive. My fiancé and I didn't tell our families yet because we wanted to go get an ultrasound picture to have when we told them. I believe I was only a few weeks along. We were back on our farm trying to get a jeep unstuck and I got on the 4-wheeler just to drive around in a circle a few times while they worked on the jeep. I hit a patch of mud and the 4-wheeler began to roll over with me on it so I fell off quickly bracing myself with my hands from hitting my stomach on the ground, luckily there was a tree beside where it happened so it caught the back end before it hit me. Later that night I felt cramps and started bleeding as if I was having a period. I then took another test a day later and it came back negative.