My friend is mad at me because of this?

Last week i missed the whole week of school because i was sick.. I had to go to the ER on thursday and then i found out i have bronchitis.. Basically my friend messaged me on facebook saying are you still sick? You have 3 tests to when you come back! and your never at school! She told me once she didn't like it when i was gone because she has nobody to talk to .. Should i give her a call? Im really nervous of going back..