Don't worry man. You just paniced, common problem for some of us weed smokers. You learn to controle it... which isn't hard, just remember your OK when you do flip out. Don't worry about your heart exploding or your gonna die, just chill. I know what your talking about though, I used to feel stoned a day after smoking when I started. It's a strange feeling, but don't worry. It WILL go away.

Also, blood tests are only effective at catching THC within what... 24 hours of smoking? Their not very effective, if it were a hair or urine test that would be diffrent...