New to ttc

I thought I couldn't get pregnant so I've never been on birth control or anything else to prevent pregnancy. After 4 years of unprotected sex I got pregnant 2 months ago but sadly I had a miscarriage. I'm scared of getting pregnant again and not knowing. How do i know when it's safe to drink medicine or continue my workout routine? I know it's safe In work out during pregnancy but I'm scared to do certain things like sit ups, feel like I'm scared to breathe 😥