@pvctom2021 Hi Tom, Swelling is your body telling you it is still healing. Fluid is accumulating in the healing tissue to wash away the blood cells, muscle cells, etc that are being shed in the healing process. You are upright and moving, so gravity carries it - to your feet.

Everyone thinks a joint replacement these days should be a breeze because the docs say "You'll be back to (your) normal (activities) in 6 weeks" - they mean you can probably go back to work, you can drive and walk, do your daily activities - you hear "I'll be completely well, ready to [golf, run a race, go on a 5 mile hike]" And you'll always have that friend who says "I was on the golf course after 4 weeks" when the truth is probably that they went to the putting green. 😉

Everything in your hip was cut, sawed, pounded on, or moved out of the way, even with the anterior approach. The surgical incision is healed, and at 3 months the implants are probably pretty solid, but muscles and nerves are still being repaired - your exercise contributes to the healing.

What can you do about the feet? First, when you do sit, elevate your feet and legs - ideally above your heart, at least above your hips. Second consider asking your doc or PT whether it would be good to wear compression socks or wraps to keep the fluid from pooling in your feet and ankles. Third there are some exercises that can help with the swelling..

These exercises will encourage the fluid to move back toward your abdominal cavity, where it can be removed by the lymphatic system & kidneys. You can find examples of any of these by looking on the Internet.
I recommend taking a look at "Bob & Brad" PT's whose humor is lame, but their suggestions are good.

Finally, the yoga pose "legs up the wall" can be helpful and relaxing.

For all of these exercises, keep in mind any precautions about angles you have. The lymphatic drainage can be done by a PT or partner. After surgery, I did legs up the wall on a bed where I could "walk" my way into position without bending more than 90 degrees.
Good luck, and congratulations on the walking and exercise! You are well on your way to complete success.
Sue