I have had extreme swelling in my legs, ankles & feet since 20 weeks, in my case it's just fluid retention, apparently making up for my petiteness! But, for other is can be a sign of pre-eclampsia, go and get your BP checked and a screen of your urine... High BP, protein in urine, headaches, visual disturbances, upper abdominal pain & swelling in the hands, face or feet are all signs of pre-eclampsia, you don't have to have all of them or even a few of them though so better to just go and get it checked out...

If, like me, all is well and your BP & Urine are fine, keep an eye on the other things for now but it's just fluid retention, our bodies are pumping alot of extra blood so circulation isn't quite what it used to be and fluid gets stuck in our legs & feet if we're on them too long, try ot get your feet elevated, preferably above your heart, the swelling should subside, also make sure you're drinking at least 3 litres of water as well, it's a bit of a push I know as we already feel bloated and can't stay off the toilet and you'd think we obviously have enough fluid haha but it does help alot, I found after a week of putting my feet up for half an hour every 4 hours and drinking the 3 litres of water, my feet were alot better, not perfect, but better... Another thing you could try is wearing compression stockings, I haven't gone down that path but it was suggested by my midwives, either way, discuss it all with your Ob/Midwives/GP, get it all checked out and they should be able to advise you on your best course of action...

Congrats on your pregnancy by the way and best of luck with everything!!

Alicia xx