Walk and legs strains easily

I’m in week 11. Same experience as you. I feel like I can walk, and I’d still walk fast, but my legs would be very tired easily, unlike previously where I could walk much longer distances. Good to listen to your body and not push yourself too far though. Still walk, because exercise is still good during pregnancy but if you feel tired or legs get sore, then just have to stop and do the walking another time or day.