thick legs

Keep drinking well.
Elevate your feet/legs if you're, for example, sitting on the couch or lying in bed. Put a cushion underneath.
Keep moving.
It's normal. Just make sure you don't get other symptoms, like a headache. That could be related to high blood pressure.
The fluid might also spread to your lower legs and hands. Sometimes your face or lips. Usually later in pregnancy. But always keep an eye on your blood pressure. Your midwife does this too.
Enjoy your pregnancy!