VO says, congratulations, your F1 Visa approved

Hi guys,
I am from Dhaka, I had my F1 visa interview on 2nd May 2013. My visa interview was like this:
VO: Good morning! can I see your I-20?
Me: Sure, here you go.
Vo: thanks, how did you manage to get all these money?
Me: I was in UK last few years, i earned these money while i was in UK.
VO: Great, where did you use to work?
Me: replied,
… VO started typing, she did not see a single document, after about a minute, she said your visa has been approved, congratulations. She gave me white paper where its instructed to check the update, VO (she) told me that when you see the status ‘issued’ then come to collect your passport. she kept my passport.

I was so happy, but after one day i track the CEAC website, it says administrative processing, ok fine. I was tracking everyday, even every hour sometimes. After 10 days they update the date, but still administrative processing. after two days of last update on 13th may, they again changed the date and says administrative processing. I am now really worried, they update the date twice. Can anybody please tell me why its still administrative processing?
I will appreciate if anybody give me a suggestion. please