Calling out of work

Yesterday I woke up with terrible body aches, chills, a sore throat, and was on the verge of having a fever. I went into work because we were short staffed, but left after a while once we were within ratio for another teacher to take over my classroom. I went to the doctor last night and was told that I have strep. I am feeling a little better today after two doses of antibiotics, but still feel sickly and have a swollen throat. I called out today because the doctor suggested that I needed to rest and that I could possibly still be contagious. I feel so bad... I never call out and even worse- I had to when we are short staffed... am I wrong for leaving early yesterday and taking the day off today?