Anxiety Attack

So I had another attack last night, and didn't get to sleep until three a.m.
I went online this morning to research this disorder I am told I have and I just don't understand how I can have an anxiety disorder when I don't have any stress in my life. I don't feel stressed or worried about anything huge, so why am I having these attacks.
The one I had last night was weird. It lasted five hours with attacks happening in small burst the whole time. It wasn't as intense as the other ones I have had but very scary and tiring none the less. I just don't know how much longer I can keep this up. Its getting to me physically and emotionally. Why am I having these all of a sudden and why do I have a constant chest tightness all day long? I just hope that the Dr I saw knows what he is doing and gave me the right answer to this problem of mine.

I will be posting in here every time I have an attack so I can keep track of them. I just really need some prays for the Lord to take this from me.