Mild swelling top of left foot & fluid-filled feeling in calf (but no swelling) for past 2 days. No redness, no pain. Sit almost all day. Lotta weird health problems lately. Went hiking last weekend.

If you have a lot. Of "weird medical problems", i would suggest starting with your primary care doc and fill them in on all these problems.
Foot Edema. Do you have thyroid problem? This left foot mild swelling can be associated with it and the hiking last weekend.