Last night I had a really bad panic attack. It lasted around 4 hours and I was pretty sure that I was going to die. I’m so confused. Nothing particularly triggering happened yesterday, this was completely random. I felt absolutely breathless and confused, for quite some time I thought I was having a heart attack. 
However I managed to calm myself down around 4am and slept but now that I’ve woken up, my hands are still shaking and my legs feel slightly wobbly. My heart is still beating fast. I’m so confused what should I do. I’ve never had a panic attack this long before. Any help/suggestions would be appreciated.