block charge double foul?

[fortmoney]

I would appreciate some insight from you experienced guys.

Girls 8th grade, both teams are pretty sloppy. Team B pressed aggressively the whole first half and, for the most part, played good, legal defense. I.e. playing close but with hands up. Team A is very untalented except for the tallest girl on the court, A1, who does most of the dribbling and shooting. A1 has broken the press and is driving down my sideline, I'm the T. I get streamlined as B1 slides over to stop the ball. In my opinion, from what I could see, B1 did not have LGP but A1 used her arm to extend and gain separation, causing B1 to fall to the ground. Since I did not see enough contact to be sure, I tried motion for B1 to get up and play on, but of course she started to tear up and A1 stopped and looked at me. I blew my whistle to stop the clock, and everyone in the gym is incredulous, both coaches and fans. I had B1 sub out of the game and we continued play with no foul assessed.

What could/should be done in this situation? Both if I had a foul as soon as it occurred, or if I stopped the game for injury, like I actually did. What could I have done better, besides get the angle between the players? I realize that is the number one mistake I made and something I've really worked hard on this season