Going down the stairs in early pregnancy

Yesterday I went to the movies and I went down the stairs. I would say it’s like if I had a two story home going down the stairs. Thank God I didn’t fall. As for my speed... I think I went at a normal speed going down the stairs. Is this really bad being 12 weeks pregnant? Today I woke up with lower calf pain. Not bad pain but more of being sore. I don’t work out at all and neither before pregnancy.