I know you need to rest it, etc, but DO NOT sit down too much.
My husband had a DVT last summer, leading to a Pulmonary Embolism (blood clots in the lungs that had travelled from the DVT at the site of his broken ankle), and when he finally got to the hospital he was down to 15% usability of his lungs.
He almost died and it was mostly my fault
because I didn't phone an ambulance, but in the 2 weeks or so before that horrible day, he'd said to his GP that he'd had pain in his lower leg every time he stood up. Turns out this was the blood being unable to get back up his leg from his bad foot due to the blood vessels being blocked with blood clots, until they dislodged.
He is okay now, after 6 months on Warfarin at the age of 33/34, but you WOULD NOT BELIEVE the number of people who have had a Pulmonary Embolism as a result of having a leg in plaster, and thus the calf muscle not contracting to push the blood back up towards the knee (this is called "muscle pump")
Get up and move around regularly, if you can wiggle your toes or move your foot up and down that's good whilst you ARE sat down, and look out for toes losing their healthy pink colour (although that didn't happen to my husband). Also, whilst you are sat down do not even THINK about crossing your legs at the ankle - that is practically guaranteed to restrict blood flow.
I do NOT wish to scaremonger, but I was completely flummoxed at a) how easily this happened to my husband in the first place, b) how many other people said that it had happened to them too, although most not as serious as DH and c) how blase the doctor was when my DH reported the pain in his leg and then when he found out about the DVT and PE. The specialist in the hospital said that if the doctor had picked up on my DH's symptoms and not just dismissed it as "the pain to be expected with a broken ankle", it could have all been prevented. 
Best wishes for a speedy recovery.