I haven't been to work for three days because I was "sick," but the truth is I was just procrastinating. I caught a usual cold, and after taking some medicine, the inflammation has stopped. However, the thought of going back to work makes me feel nauseous. I didn't show up on Saturday, which was payday, and I received a call from HR asking when I could come in and for a medical certificate. Right now, I only have a headache and a sore throat, but I'm mentally exhausted and don't want to return. I'm considering resigning, but I'm unsure how to go about it.