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.
A man expressing anxiety while taking a test. noun. Anxiety is defined as a feeling of being nervous or worried, often as a result of fear of a possible future event. An example of anxiety is the feeling you get before a test for which you have not studied. The definition of anxiety is an eager, strong desire.