I have been very fatigue and listless over the past two moths. Started of as just being tired for about 3 weeks, do not know if I had low grade fever did not check, no nausea, no rash. After 4 weeks of this swelling of neck on left side and just to the right of adams apple. Went to ER, just gave me muscle relaxer. Going to see my GP and take Mono Spot on Monday. Is it uncommon to get mono at 40 years old or some underlying issue? I do not recall having this as a youth. Seems to be dragging on.