Sick note

I'm feeling very poorly for 5 days already but suppose to be on college today and tomorrow but I can't drive 2 h until campus or have another transport beeing a single mom with my kids sick as well . I was email the college to let them know and send them a sick note from doctor online I have from work and they answer me back is not valid how is that possible if gp keep me 1 h on the waiting list and no want help me give me a paper sick note telling him the sympyoms I'm having feeling dizzy,cough until vomit,chills and high temperature? Is not possible the system în this country I'm just so disappointed, please give me an advice what I can do?Thank you!