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.
Anxiety is a feeling of fear or uneasiness. Mild anxiety is part of every day life. You might feel anxious before you take a test or attend an important meeting at work. This kind of anxiety can help you by making you more alert or careful. Mild anxiety goes away after you're out of the situation that caused it.