19 weeks pregnant and running

Well...I went running today. I started way to fast and then realized if I was breathing so hard the baby probably wasn't getting much oxygen so I walked for a bit and then jogged really slow for the rest of my run. I think I ran about 1 1/2 miles and walked 1/2 mile. It was really nice but I'm not sure if I should keep it up or just start walking again. Who knows. I am excited to find out what we are having on Thursday. Hope all is well.