VERY Slow heart rate and fatigue HELLLLLPPPPPPPPPPPP?

right now i havent slept and its almost 7AM and its becuase every time i go to lay down or even sit for too long my heart rate goes from about normal to almost nonexistent and i freak out and ive been getting dizzy/fatigued on and off allnight. idk what to do im afraid its going to stop beating any second