I get anxious or sad suddenly. A vacuum.

I have started getting anxiety attacks all of a sudden for almost 6-8 months now. They happen randomly and suddenly. I get panic attacks, even when I am doing menial jobs or jobs I am actually good at. Interacting with people is becoming harder. I have become insomniac. I cannot sleep. Even if I do, I sleep lightly and get horrifying nightmares. My nightmares are extremely graphic and detailed, details I remember for days afterwards perfectly well. I start getting unnecessarily sad all of a sudden. I do not even know why I get sad. I will be dancing one moment and the next, I will be standing like a dead person, extremely sad. Worst part is I do not even know when these transitions will strike me. They are extremely random. I have lost all force in life. I used to love to run and I used to jog for at least 5 km everyday. Now, getting out of bed is a task. I miss classes saying I want to study but I cannot study. I will physically sit with my friends but mentally, I am in a vacuum.