Opportunistic infections (OIs) are infections that occur more frequently and are more severe in individuals with weakened immune systems, including people with HIV.
Being nostalgic means to miss the past time. It seems that a real life was in the past because now in the present is different, probably things changed and we know that never is going to be the same. It leads to a nostalgic feeling.
Etymology: L, anxietas + state. a mental or emotional reaction characterized by apprehension, uncertainty, and irrational fear. Anxiety states may be accompanied by physiologic changes such as diaphoresis, tremors, rapid heartbeat, dilated pupils, and xerostomia.