Sorry for so many question but I just want to travel a little more relax.

Why when I arrived in Houston, TX (04/01/2013) they asked me to put my fingerprint and take picture twice? Then, brought me to one small room to check information. After that a woman looked all my documents, she asked me if I knew why I was there and I said no. Then she told me "Because appeared in your file you were arrested. But your case is dropped so you are fine. Are you going to be here just this month (april)?" I answered yes and she gave me my passport and nothing was flagged there. I got 6 months normally. I didn't stay 6 months. Just one month and a half.

I still have my valid visa. I just want to be 'sure' (I know I can't be 100% sure) that will be ok.
Do you think I will be ok?

Thank you so much for attention!