Toy really require an in-person evaluation because there are serious problems that can cause such swelling. In the meantime, start on 2000 mg of vitamin C a day (2 grams), divided throughout the day, preferably on crystaline form (not tablets). Vitamin C is a mild diuretic.
u may just be retaining fluid. keep your legs elevated at night, and maybe try taking a water pill.
There could be so many causes - are you on any new medications? This is a cause that many people fail to consider... if not, I would google the symptom and maybe cross off all that you think most likely do not apply.....
When you press on it firmly, does it leave a dent?
There is a difference between this kind of thing when it leaves a dent (pitting) and when it doesn't (non-pitting).
Oedema (edema) can be caused by a salt imbalance, but may signify a dangerous underlying condition.
Read about it more here: https://en.wikipedia.org/wiki/Edema