Since I developed pots in february I've been highly inactive. I walk around every few hours and change positions a lot but my mom worries I could get a clot. Is that likely? Not overweight.

Get active. Your clotting risk is low, but inactivity is not healthy even if your weight is normal. You are losing muscle mass and cardiac reserve. Please talk to your doctor about treating your pots more aggresively.
Please define pots. Walking is good exercise but not the only way to stop a clot. If you had a clot before i assume you're physician as you on anti-clotting therapy. You would be best to discuss this strategy with your physician.