I dont sleep well, I worry constantly all day ...

Ive had an awful week!! I was diagnoised with anxiety back in 2005, I have had it off and on since then. I went through lots of test back in 2005 and everything came out ok. Since september of 2011 I have started having more and more anxiety issues coming up. This week it has gotten a lot worse...I feel like something is really wrong with me. If i had those test ran in 2005, do i need to have them done again?? I just dont know what to do!! I dont sleep well, I worry constantly all day about my health and im afraid im having a heart attack. please give me some advice to be able to tell what the difference is?? When should i go get help or go to the ER??