3rd trimester workout slowed down

I'm 31 weeks now and I'm slowing down. I think the only thing that I can do now that doesn't feel like I'm over exerting is walking. Lifting, squats, etc makes my heart rate go up to fast. I'm getting 10,000 steps in just fine, but I think it's time to call it quits for everything else. I'm a little discouraged because I love working out. Anyone else get to this point around 30 weeks?