What Could Extreme Pressure In Head Suggest?

My Head feels light,its like head pressure unlike headaches.Sense of impending death.I have this fear of losing control or going insane. I feel like im choking and having shortness of breath . I feel depersonalization at times !! I always check my pluse to check if my heartbeat is fine. I fear this thing thats happening to me !! it happens everyday for the past 2 months.help ??