Did I already blow my interview? Help?

A company asked me via email if I would be available at 7:45 next wednesday for a job interview. I got this Email yesterday. I said "Sounds Good. So 7:45 on July 6th? Is it possible I could get the address?. And now I haven't received a reply in over 18 hours. Did I blow it? I ended up googling the place and finding directions without their help,but since they didn't tell me where they were located that would seem creepy. So did I run my own chances?