Why am I so tired/weak?

So I basically have been conjested n full of mucus n coughing since Christmas Day. In bed couldnt get up for a few days. Now I can get up and stuff but it's Monday and I'm still super weak. My doctor today said I dont' have bronchitis but gave me some meds but he says I am exhausted cuz of anxiety and stress. Do u think thats all it is? I don't feel 100% and I feel like by now I should be good to go but I'm not. I have no energy and I could sleep all day. It's harder for me to fall asleep at night though. Do I feel this way because I have been doing nothing but laying around? I dont have the symptoms of mono, no fever, no chills, no sore throat. Just tired, weak, no energy, conjested. Is it normal that I still feel tired and weak after like 5 days?