Is it my achilles? torn? Strained?

Hi. I did something to my left achilles a week ago–either while jogging on the treadmill or on my bike, not sure. I’m 30, female, and in good weight & phys. condition. I usually walk 3 miles a day but one day I started jogging a bit on the treadmill and I think it started hurting then. I thought it was my shoes and just tried to walk it out, the pain continued a few days and I kept walking, until it got so bad that I was limping when I’d get off the treadmill and was in serious pain while walking on it. I realized I had been walking with my foot turned at an angle to try to avoid a bit of pain. I finally took yesterday and today off because my foot has completely swelled up–huge, all around the ankle & achilles area. Strangely, now my other foot feels a little achy and like there is fluid beneath the ankle.Sorry to be so lengthy–but what did I do, and what can I do to help it? I love my daily walks! Should I have a DR look at it to be sure it’s not torn? Thanks for your help!