Working Out

I used to workout pretty regularly before getting pregnant. I tried to 5-6 days a week. Usually in consisted of a 30 min walk a long with some form of strength training. I couldn’t bring myself to work out the first trimester. Every time I tried I got really close to throwing up. I want to get back at but safely and slowly. Any recommendations? Anyone face something similar? I’m thinking daily walks a light prenatal yoga. Also almost all prenatal workouts I see involve some for of being on your back. I thought that was a no go. Are you able to for short periods? Any advice is appreciated!